Or the smooth, majestic, 17-time Grand Slam winner Roger Federer?
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Anyone dare to call Sunday's US Open final? Nope, me neither. Although I'll let you into a not-so-secret bit of info - Federer leads 21-20 in the head-to-head against his great rival.
Make any difference? Probably not. But it gives you a little something to occupy your mind when thinking about the outcome.
Right it is time for us to say goodbye. We will be back tomorrow for the women's final and of course will return on Sunday. See you then!
Player reaction
Wawrinka 4-6 3-6 1-6 Federer
Roger Federer: "Novak has had a tremendous year, there's always a lot on the line when we play. He's the best mover on the hard courts, he's tough mentally, but I like that challenge and I'll be ready for it.
"Serena has done unbelievably well, maybe it just wasn't meant to be. We're lucky that she's still playing tennis."
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Liam Walton: Federer is just unbelievable. Even at the age of 34, he makes it look so easy! Class is permanent.
Player reaction
Wawrinka 4-6 3-6 1-6 Federer
Roger Federer: "Obviously I am very happy. It's been a great tournament so far - I have tried so hard over the last six years to the get back into the final, and tonight it worked.
"I'm serving very well, I'm going for my shots, I'm playing positive tennis. I practised for years in front of nobody, I'm not going to throw away moments like this."
Federer reaches US Open final
Wawrinka 4-6 3-6 1-6 Federer
Stan Wawrinka trudges off court looking slightly shellshocked - he has been hit by the Fed Express. Rather like Marin Cilic before him, he didn't have the opportunity to lay a glove on his illustrious opponent. The two Swiss men warmly embrace at the net - I don't think I could be so gracious to someone who has just thumped me in front of 20,000 people.
Stan will move up to fourth in the world rankings after this tournament. Scant consolation.
Federer reaches US Open final
Wawrinka 4-6 3-6 1-6 Federer
That routine win - which has taken just 92 minutes - means second seed Roger Federer will meet top seed Novak Djokovic in Sunday's final. I think those two are quite familiar with each other....
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Russell Fuller
BBC tennis correspondent on Radio 5 live Sports Extra
"You run out of superlatives. There is nothing that Stan Wawrinka can do to stop the Roger Federer juggernaut rolling artistically onward."
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"The fans are on their feet clapping as if Federer has just finished a concerto."
Game, set and match - Federer
Wawrinka 4-6 3-6 1-6 Federer
ReutersCopyright: Reuters
Wawrinka threatens to make Federer wait at 15-30, but then again has no answer to Federer. That brings up match point - and a huge roar of anticipation from the Ashe crowd. Wait - Stan isn't going without a fight. A trademark backhand winner down the line makes Roger hold on.
But not for long, Federer tees up a second match point - and blasts an ace down the middle. Job done.
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Wawrinka 4-6 3-6 1-5 Federer*
So here we go. With less than 90 minutes on the clock, Roger Federer is serving for the match....
Federer breaks
Wawrinka 4-6 3-6 1-5 Federer*
We think we've cracked what is making Roger Federer so difficult for Stan Wawrinka to get near. Not the dreamy forehands or sensational serves. Not the precision punches or his anticipation. Nope, it is the eye-squinting colour of neon pink trainers. Poor old Stan's sight is being dazzled.
Of course we jest - Federer has been simply off the scale. As illustrated as he racks up another break point. Wawrinka tries every plan of attack that he has, but Federer's defence holds firm as they trade blows in a long rally. And it is the fifth seed who crumbles first, slapping a frustrated forehand into the net.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Federer is really in the zone. He looks really mentally fresh. He's getting more sleep now, because his kids have grown up a little."
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Russell Fuller
BBC tennis correspondent on Radio 5 live Sports Extra
"It's almost like Federer is in a race with Novak Djokovic. This goes down as more impressive. It's a remarkable demolition."
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*Wawrinka 4-6 3-6 1-4 Federer
Following up the break of serve with a booming ace is exactly what Federer could have hoped for. And that's exactly what he gets. That sets the platform for a comfortable hold - save for a stray backhand for 40-15 - and leaves Federer two games from yet another US Open final.
Federer breaks
Wawrinka 4-6 3-6 1-3 Federer*
Getty ImagesCopyright: Getty Images
How important could this point be? A match winner for Federer? Quite possibly. The game is delicately poised at 30-30 as the pair become embroiled in a baseline shootout. Duh duh duh...Wawrinka blinks first to hand a break point to Federer. And another unforced error from Wawrinka - this time going long - puts Fedrer on course to wrap this up quick sharp.
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*Wawrinka 4-6 3-6 1-2 Federer
Federer is purring like a cat which has just devoured a saucer of the finest cream on the planet. His smooth serve peppers the Wawrinka defence, finishing off his rival with a forehand smash.
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Wawrinka 4-6 3-6 1-1 Federer*
Solid hold from Wawrinka, allowing Federer just the one point. Unfortunately solid holds alone aren't going to stick the fifth seed in the US Open final. He needs a breakthrough....
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*Wawrinka 4-6 3-6 0-1 Federer
Thanks James. During the changeover Wawrinka would have been sat in his chair, dreaming of a morale-boosting break at the start of the third set. A rare double fault from Federer gives him a whiff of one at 40-30, but then slams the door shut on his Swiss compatriot. Stan is not the man as his usually faultless backhand crashes into the net.
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Here's Jonathan Jurejko to take you through to the conclusion...
Federer wins second set
Wawrinka 4-6 3-6 Federer*
Wawrinka is under siege. This is a man who has won two Grand Slam titles and he quite literally doesn't know what to do. Such is Federer's brilliance, he's reduced to trying impossible winners and hopelessly over-ambitious trick shots.
He balloons a forehand long to bring up 0-40 and three set points. Federer needs only one. A seventh US Open final is in sight.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Quote Message: I'm not sure what I like more - a nice cup of chocolate mousse or watching Roger Federer win so smoothly. It's delectable.
I'm not sure what I like more - a nice cup of chocolate mousse or watching Roger Federer win so smoothly. It's delectable.
*Wawrinka 4-6 3-5 Federer
This is glorious, artistic tennis from Federer. He's going through the whole repertoire at the moment. When Wawrinka tries to put a smash into the empty court, Federer is there. When Wawrinka tries to lob him, Federer somehow scrambles back and manages to flick it disdainfully back past him. Wawrinka can't lay a glove on him.
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Russell Fuller
BBC tennis correspondent
Quote Message: It is going to be so tough for Stan to keep having to save break points. All the momentum is going against him at the moment.
It is going to be so tough for Stan to keep having to save break points. All the momentum is going against him at the moment.
Federer breaks
Wawrinka 4-6 3-4 Federer*
The scoreboard might be all square - but there's no doubt who is under the more pressure. A mishit from Federer forces Wawrinka back, and suddenly he's in trouble again at 0-30. Stan goes long and Federer has three break points. Wawrinka fires long again, and Federer is in charge in the second set.
*Wawrinka 4-6 3-3 Federer
The Federer serve is well and truly firing. The ball toss, the arch of the back, the rapid arm all flowing in one seamless movement - the ball more often than not kissing the corner of the service on its way past Wawrinka. If that doesn't work, saunter to the net and poke a volley past Stan. Easy peasy.
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Russell Fuller
BBC tennis correspondent on 5 live sports extra
Quote Message: Most players are used to hearing the crowd supporting Roger Federer. Poor old Stan. Novak Djokovic might even have to face the same on Sunday.
Most players are used to hearing the crowd supporting Roger Federer. Poor old Stan. Novak Djokovic might even have to face the same on Sunday.
Wawrinka 4-6 3-2 Federer*
*denotes next to serve
If Federer was a boxer, he wouldn't just have quick hands and a pretty left hook, he'd also be adept at soaking up punishment. He rides a couple of huge groundstrokes from Wawrinka and loops a big forehand winner into the corner.
Wawrinka sends a simple volley into the net and it's break point Federer. A big serve comes to Stan's rescue. Then it's another pistols-at-dawn point at the net, with Federer emerging victorious with a volleyed winner.
Another break point, but Stan closes it out with a good volley of his own, which he follows with a bellowed 'Come on!' Two big serves, and he's in the clear.
*Wawrinka 4-6 2-2 Federer
Wawrinka garnered a lot of attention during the French Open for wearing shorts that were more garish than a hippie's tablecloth, but disappointingly, he's bedecked in a crisp white pair today.
Federer rattles through another brisk game, scooting to net to punch away a couple of volleys. We remain on serve.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Quote Message: Stan is trying to overpower Roger but he needs to use that slice to set up shots that he can rip winners off with. And he needs to see when Roger is sneaking in on the run. He has a great passing shot - he's just not utilising it yet.
Stan is trying to overpower Roger but he needs to use that slice to set up shots that he can rip winners off with. And he needs to see when Roger is sneaking in on the run. He has a great passing shot - he's just not utilising it yet.
Wawrinka 4-6 2-1 Federer*
Federer tries to charge the serve again, but this time he finds the net. A booming backhand down the line takes Wawrinka to 40-0, and Federer coughs up the game when he nets a forehand.
*Wawrinka 4-6 1-1 Federer
Bradley Cooper is in the audience. So far today we've seen him, Sean Connery and Canadian rapper Drake, which coincidentally is the line-up for my dream dinner party.
Talking of dreams, Roger Federer's serve is pretty dreamy - he finds the corners with pinpoint accuracy for an impressive hold to love.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Quote Message: In the first set Stan had break points on the opening game of Federer's serve and didn't break. In this set, Federer had a break point and didn't break. But Federer turned around in the next game and broke. Let's see if that pattern continues.
In the first set Stan had break points on the opening game of Federer's serve and didn't break. In this set, Federer had a break point and didn't break. But Federer turned around in the next game and broke. Let's see if that pattern continues.
Wawrinka 4-6 1-0 Federer*
* denotes next to serve
Wawrinka, by the way, is yet to beat Federer on hard courts - he's 0 for 8, as the Americans say. This is a must-win set for the fourth seed.
A double-fault and a typically picturesque leaping forehand from Federer take him to 30-30, and he opens up the court masterfully to give himself a forehand down the line for break point.
Terrific response from Stan, bludgeoning an inside-out forehand into the corner. Two big serves complete the escape act, and that's a big hold.
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John McEnerney: Fed looking majestic but Stan is no slouch this hopefully will go the distance after that walkover by Novak. Federer in four.
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Sara Orchard
BBC Radio 5 live sports extra commentator
Quote Message: The style Roger Federer is playing is so exciting, so different and Stan hasn't found a reply.
The style Roger Federer is playing is so exciting, so different and Stan hasn't found a reply.
Federer wins first set
*Wawrinka 4-6 Federer
Now look, I'm a modern man, in touch with my feminine side and all that, but I'm not sure I'd be too comfortable wearing the Federer get up down the local municipal courts. White polo with pink collar and piping, shorts with pink piping, pink wristbands and pink trainers. It's...zingy.
Still, it's not doing Federer any harm out there - a slightly too aggressive Wawrinka sends some potent groundstrokes over the baseline and into the net to bring up two set points. Another forehand flies long from Stan, and that's the set.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Quote Message: Stan's first serve percentage is only 39%. He needs to change up his first serves with some serves that he knows 100% will go in and it will also keep Roger off balance. When Roger locks into a shot you're hitting to him repeatedly, you're done.
Stan's first serve percentage is only 39%. He needs to change up his first serves with some serves that he knows 100% will go in and it will also keep Roger off balance. When Roger locks into a shot you're hitting to him repeatedly, you're done.
Wawrinka 4-5 Federer*
* denotes next to serve
One thing Federer has been brilliant at over the years is sending the ball about a gnat's width over the net with the velocity of a speeding asteroid - Wawrinka comes to net to dispatch a volley but suddenly finds the ball at his bootlaces and can't get it over the net. 30-30.
Stan again targets Federer, sending a smash straight at him to bring up 40-30, and he closes the deal. Fed will serve for it.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Quote Message: Federer is changing his racquet for a third time - I think he wants a tighter racquet to respond to Stan's serve.
Federer is changing his racquet for a third time - I think he wants a tighter racquet to respond to Stan's serve.
*Wawrinka 3-5 Federer
Now, I know the Swiss are a peace-loving nation. And yes, yes, these two are great pals, yadda yadda. But if my imagination doesn't deceive me, Stan is going for Roger here. He's trying to foil Fed's sneaky tactic of rushing to net with the not-so-subtle strategy of absolutely leathering the ball at him when he gets there.
It works as he almost takes the racket out of Roger's hand, bringing up 15-30, but Federer gets himself out of trouble with three straight points.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Quote Message: That was a sick volley and unreal get by Federer - I actually thought he had won the point.
That was a sick volley and unreal get by Federer - I actually thought he had won the point.
Wawrinka 3-4 Federer*
Oh my word. Wawrinka looks to be cruising at 40-15, but he sends a forehand long. Can Federer get to deuce? Wawrinka absolutely nails a smash at 40-30, but Federer, inescapable as time, is there, somehow, and absolutely pings it right off the strings about an inch over the net. Stan is equal to it though and nonchalantly knifes the volley into the open court. That is what Alan Partridge would call liquid tennis.
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Jeff Tarango
Former professional tennis player
Quote Message: That charge forward and volley from Roger Federer was reminiscent of his coach Stefan Edberg - that's why I've been calling him Fed-berg.
That charge forward and volley from Roger Federer was reminiscent of his coach Stefan Edberg - that's why I've been calling him Fed-berg.
*Wawrinka 2-4 Federer
Federer's usual gossamer touch deserts him at the net as a drop volley sits up for Wawrinka to smack a passing winner past him, and suddenly Stan has 0-40 and three break points.
Federer saves the first two with an ace and a putaway, and he fends off the third with a display of real cojones - following a second serve into the net and painting the sideline with a volley. He closes out a Houdini-esque hold with an ace.
Wawrinka 2-3 Federer*
* denotes next to serve
That'll make Stan feel better - absolutely torching a backhand winner past Fed to get to 40-0. That one left scorchmarks on the court. Federer then dumps one into the net and Wawrinka remains in touch.
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Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
Quote Message: It was important for Federer to get on top early in the match - that is how he has won a lot of his matches. That is a huge break.
It was important for Federer to get on top early in the match - that is how he has won a lot of his matches. That is a huge break.
*Wawrinka 1-3 Federer
Federer may be 34, but there's still some elastic in that serving arm - the ball is clearing the spectators in the first row as it bounces past the flailing Wawrinka. A couple of howitzer deliveries help Federer to a love hold.
Federer breaks
Wawrinka 1-2 Federer*
Now then, here's the Roger Federer sneak attack that we've been hearing so much about. In case you haven't keeping your ear to the tennis grapevine, Fed has caused a few ripples by charging into the net to take his opponent's serve halfway up the court. It fails the first time, by on the next point it works and Wawrinka nets.
The tactic clearly unsettles Wawrinka and he pings a forehand off the tape and into the tramlines to bring up break point. Wawrinka sends a forehand long, and it's first blood to Federer.
*Wawrinka 1-1 Federer
On 5 live, Jill Craybas reckons that you can tell by the way Stan uses his walk, he's a US Open contender, no time to talk. Or words to that effect. He certainly carries a bit of a spring in his step.
But then again the man across the net, resplendent in pink sweatbands today, has never been known for a lack of confidence either. Federer fends off a minor hiccup at 30-30 with a good approach, but then Wawrinka stings him a crisp one-hander down at his toes. Deuce.
Fed sends one into orbit off the frame, and suddenly he's staring down the barrel of a break point. Stan shanks the return, and then sees an ace whizz past him at nostril height. Wawrinka sends a backhand long, and Rog is on the board.
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Christopher David: Currently contemplating how long I stay up to watch this undoubted classic Federer/Wawrinka match.
Wawrinka 1-0 Federer*
* denotes next to serve
Woof. Plenty of mustard on the Wawrinka serve, and he's up and running with a simple hold.
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Here we go. It's Wawrinka to serve first...
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BBC SportCopyright: BBC Sport
Swiss spat
Roger Federer v Stan Wawrinka
But then again, he's got a formidable obstacle in his path: Stan Wawrinka, undoubtedly the most improved player on tour over the past couple of years.
These two have had a complicated relationship. For many years, they were great friends, enjoying some great times together, including winning gold at the 2008 Olympics.
But the Swiss neutrality was rather soured last year when Federer and Wawrinka had a spat at the ATP Tour Finals, apparently sparked by Mrs Federer calling Wawrinka a "crybaby".
The two of them thrashed it out in the locker room, we're told. But who knows, if this one goes the distance, is it too much to hope it could get a little bit spicy?
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BBC SportCopyright: BBC Sport
Fabulous Fed
Roger Federer v Stan Wawrinka
Let's begin with a consideration of Roger Federer - a man who has used up all the superlatives in the dictionary, and all the space on his mantlepiece over a glittering 16-year career.
You keep waiting for Federer to lose it. To enter a terminal decline. But no, at 34, he seems to be playing better than ever. Heck, he's won his last 35 sets. Could he finally clinch his 18th Grand Slam? You wouldn't bet against it...
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Thank you JJ. Well, what a strange day it's been at Flushing Meadows. Simona Halep taken to the cleaners. Serena Williams losing from a set up against the world number 43. And now, the defending men's champion booted out the back door on the back of the most one-sided semi-final in the Open era.
What surprises might Federer v Wawrinka have in store? We wait to find out...
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Federer v Wawrinka
So the identity of one US Open men's finalist is known. But who is the top seed going to face? One thing is certain - it will be a Swiss fella.
Good job that the Alpine nation is well-known for being a 'neutral' country as two of their stars scrap for a place in the Flushing Meadows final.
Getty ImagesCopyright: Getty Images
Here's my team-mate James Gheerbrant to talk you through all things Swiss....
Djokovic reaches US Open final
Djokovic 6-0 6-1 6-2 Cilic
As if the scoreline doesn't already tell you everything, here are a few more numbers to make Marin Cilic wince. The key stat being that Cilic made 37 unforced errors compared to Djokovic's 13. And the top seed won 87 points in total, dwarfing the 39 earned by Cilic.
Player reaction
Novak Djokovic: "I'm very proud to have reached all four Grand Slam finals. I haven't been very successful in the finals of the US Open - I have won one and lost four. But I can promise I will give it my best. I will definitely get ready to play against a Swiss player!
"Serena is a great champion, she is somebody I respect a lot, it wasn't to be today but it takes nothing away from what she has achieved in her career."
Player reaction
Djokovic 6-0 6-1 6-2 Cilic
Novak Djokovic: "Marin was carrying an injury, he was courageous to come out and finish the match, so applause to him.
"I came out with good focus and good intensity and executed the gameplan."
Djokovic reaches US Open final
Djokovic 6-0 6-1 6-2 Cilic
Novak Djokovic is grinning like a Cheshire Cat as he addresses the Arthur Ashe Stadium after that routine win. He admits he is hoping to rectify his poor record in the Flushing Meadows final - winning one and losing four - on Sunday. There he will face one of Swiss pair Roger Federer or Stan Wawrinka who are next on the star-studded US Open bill.
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Jill Craybas
Former world number 39 on BBC Radio 5 live Sports Extra
"It's a shame - Cilic obviously isn't feeling 100%. He fought his hardest, but he couldn't move today, he couldn't give his best."
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Djokovic 6-0 6-1 6-2 Cilic
It is hard not to feel some sympathy for Marin Cilic. Novak Djokovic made him look like a club player rather than a Grand Slam winner. Although, as Novak graciously points out in his on-court interview, the ninth seed has been struggling with an ankle injury over the past couple of matches. Did that have a part to play in Cilic's no-show? Probably - sure we will find out more about that a little later on.
Game, set and match - Djokovic
Djokovic 6-0 6-1 6-2 Cilic
Getty ImagesCopyright: Getty Images
Stunning stuff. Novak Djokovic brings an overhand backhand smash to the party, giving himself three match points. Second serve....Cilic returns....Novak plants a forehand into the net. One down. But Cilic coughs up the second, a long baseline rally ending when the Croatian clunks a forehand long. He couldn't wait to escape from Ashe....
Djokovic breaks
Djokovic 6-0 6-1 5-2 Cilic*
Don't you hate those people who say 'I told you so'? Well, I told you so. Novak Djokovic does not look like he needs two service games to see of Marin Cilic. More errors from the Croatian gift three break points to Djokovic, who snaffles the first one. The record for the least number of games lost in a US Open semi-final? Four. And that came in 2001 when Lleyton Hewitt beat Yevgeny Kafelnikov...
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Djokovic 6-0 6-1 4-2 Cilic*
Novak Djokovic is two service games away from his sixth US Open final - and it might not even take him that long. Cilic takes the first point in game eight of the third set, only for the Serb to wipe that out with an ace before going on to clinch the hold without further damage.
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David Law
BBC Radio 5 live Sports Extra commentator
"Cilic is giving everything he's got. He's not short-changing the fans at all. But they are watching a masterclass from Djokovic."
Djokovic breaks
*Djokovic 6-0 6-1 3-2 Cilic
ReutersCopyright: Reuters
Beware the wounded world number one. Cilic's break in the last game was only the eighth time that Djokovic has not held his serve in this tournament - and he didn't like it. He goes on the attack against the Croatian, teeing up two break points and nabbing the first one. As you were...
Cilic breaks
Djokovic 6-0 6-1 2-2 Cilic*
Cilic glances up towards the scoreboard at 30-15 - don't do it, Marin. He looks dazed and confused - rather like a man who has been released into everyday society after a period of captivity.
But the stark realisation of the numbers do seem to jolt him into life. A brilliant forehand winner helps him tee up a break point. Yes, you have read that right - Marin Cilic has a break point. And he takes it!
High-quality stuff from the defending US Open champion, whose neat dropshot is even too much for Djokovic to rescue. A bald gentleman wearing a Croatian football shirt and red and white paint on said follically-challenged cranium claps heartily - as does the rest of Ashe.
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Jill Craybas
Former world number 39 on BBC Radio 5 live Sports Extra
"That was a better game from Cilic. He's still struggling, but at least he tried to play the right style of tennis: big serve and big forehand."
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*Djokovic 6-0 6-1 2-1 Cilic
Marin Cilic manages to salvage some pride with his best service game of the evening. And he even manages to cook up a double fault in this. The Croatian cruises into a 40-0 advantage with an ace, has a little wobble with a couple of shocking serves, then regains his composure to win the game with a crunching forehand down the line.
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David Law
BBC Radio 5 live Sports Extra commentator
"In this sort of form, Novak Djokovic is going to take some stopping at this US Open."
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Djokovic 6-0 6-1 2-0 Cilic*
APCopyright: AP
Move along, nothing to see here. Apart from more Djokovic brilliance that is. The top seed holds out to love again, sealing the game with a scrumptious lob that a scrabbling Cilic manages to reach but can't stick back over the net.
Djokovic breaks
*Djokovic 6-0 6-1 1-0 Cilic
Anyone giving Cilic any chance of winning a set? The most optimistic - or sympathetic - fans might have done about one minute ago - not now.
The Ashe crowd try to gee up Cilic after he bangs an ace down the T for 15-30, before Djokovic curses himself for overcooking a backhand down the line. Chill out Novak, you're coasting.
Luckily Cilic is feeling charitable today, handing over a break at the first opportunity.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic should pull the plug. There's nothing Goran Ivanisevic can say to him to spark him into life."
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David Law
BBC Radio 5 live Sports Extra commentator
"You've got to give Djokovic massive credit. He is so tunnel-visioned about what he wants to do. He's a great friend of Marin Cilic but that counts for nothing."
Game and second set - Djokovic
Djokovic 6-0 6-1 Cilic
Incredible. Wonderful. Clinical. Insert any other superlative of your choice. Djokovic gives the tiniest whiff of hope to Cilic at 30-30, before snatching it out of his hands with a second ace of the match and an aggressive forehand down the line. Cilic doesn't know what day it is.
Double break for Djokovic
*Djokovic 6-0 5-1 Cilic
AFPCopyright: AFP
If this was a boxing match then the referee would be stepping in. Djokovic earns another break of the Croatian's serve - now he is serving for the second set. Cilic goes 30-15 up and then pulls out a 106mph second serve which Djokovic duly spanks a blistering crosscourt forehand. Wow. That knocks the stuffing out of Cilic, who meekly surrenders the final two points.
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Djokovic 6-0 4-1 Cilic*
Novak Djokovic is rattling through his service games quicker than a comedian goes through one-liners. But Marin Cilic isn't laughing. Djokovic generously allows Cilic a first point of the second set against his serve, only for the Croatian to repay the favour with another unforced error - a lazy forehand into the net - to seal the game in the Serb's favour.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"I think Goran Ivanisevic [Cilic's coach] might get up and walk out. I'm not sure what's going on inside his head right now - I imagine it looks like a lava fireball."
Djokovic breaks
*Djokovic 6-0 3-1 Cilic
Stop the clock! We're 42 minutes into this, ahem, contest and we see our first poor shot from Novak Djokovic. The Serb looks to the heavens as he plants a weak forehand into the net at 30-15. But soon it is Cilic grimacing again. Another break point to Djokovic when the Croatian crumbles after a long baseline rally, then another forehand unforced error gifts the first break of the second set to the world number one.
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David Law
BBC Radio 5 live Sports Extra commentator
"It's almost as if Cilic isn't in the right place for some of these shots. His footwork isn't dynamic enough."
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Djokovic 6-0 2-1 Cilic*
ReutersCopyright: Reuters
How would 007 get out of a scrape like this? With some smooth talking and a cunning escape plan probably. Let's hope Marin Cilic, who sees another Djokovic service game to love flash past him, has got the latter. If not then he might want to grab a quick word with Sean Connery at the changeover. A Cilic comeback? Never say never, again...
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*Djokovic 6-0 1-1 Cilic
The person who is operating the Cilic side of the scoreboard had better wake up. We need him. The Croatian finally sees a number go next to his name when Djokovic misses the target by a matter of millimetres with a crosscourt forehand. Huge cheers (maybe some ironic) from the Ashe crowd...
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Djokovic 6-0 1-0 Cilic*
Any chance of Novak Djokovic easing off? Nope. The Serb tees up another break point with some unreturnable returning, although Cilic saves that with a handy first serve which is too hot for Djokovic to handle.
But another unforced error from Cilic - a long backhand under little pressure in a routine rally - sets up a second break point for Djokovic.
Again Cilic scrambles the game back in his favour, setting up his first game point of the match - in the EIGHTH game. However, he cannot convert...
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"This is starting to look like clean up on Aisle Six."
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Djokovic 6-0 1-0 Cilic*
This is X-rated stuff from Novak Djokovic. The match needs a 'Parental Advisory' warning - it is a brutal assault on Marin Cilic. The Croatian has no answer to the Serb's service game, which is over to love in almost a blink of an eye.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic has won 15% of second-serve points, and he's only got 41% of his first serves in. You've got one player who's fresh as a daisy and another guy who's at the end of his string: that's why it's lopsided."
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David Law
BBC Radio 5 live Sports Extra commentator
"It's difficult to think how Cilic can even make a fight of this, the way it's going. There's about 20,000 people in here and they're getting nothing like a contest - you can hear a pin drop."
Game and first set - Djokovic
Djokovic 6-0 Cilic
Unbelievable stuff. Djokovic misses a second set point - but makes no mistake with a third. The top seed's movement has caused all sorts of bother for the ninth seed, who crumbles in just 24 minutes.
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Djokovic 5-0 Cilic*
Oh dear. Marin Cilic almost knocks out a ball boy with a wild swipe that is nearer the spectators' gangway than the tramline as he goes 15-0 down.
A decent first serve is a confidence booster if nothing else - as is a humdinger of a serve which flashes past Djokovic's eyeline for his first ace of the match.
But another unforced error from the baseline hands another break point to Djokovic. The Croatian pulls out a beautiful dropshot that floats over the net and touches white paint. Deuce...
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Djokovic 5-0 Cilic*
Novak Djokovic holds comfortably to 15 and then gives his face a good rub with his towel as he sits back down. I don't know why - he has hardly broken sweat. Marin Cilic, on the other hand, will be feeling rather nervous. Apparently he has only been bagelled once this year. His opponent? The bloke staring across the net from him. Novak another break of serve away from the first set....
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic isn't setting up very well. The little adjustment steps with his feet just aren't there. He's not assessing the shots well, and Novak's varying his serve, so Cilic isn't timing it that well."
Double break for Djokovic
*Djokovic 4-0 Cilic
Wow. Cilic thinks he is on the attack, whipping a forehand down the line. But Djokovic turns defence into offense quicker than Barcelona's football team. A wonderful winner down the line leaves Cilic's coach Goran Ivanisevic looking glum, although the former Slam winner's expression becomes cheerier as his man battles back to 30-30.
Cilic looks to get on top in a long rally, pounding a forehand into the corner. But Djokovic pulls a double-handed backhand out of the top drawer, forcing Cilic to volley into the net. Another break point. And then Cilic crumbles. Double fault from the ninth seed hands the game to Djokovic on a silver plate.
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Djokovic 3-0 Cilic*
Marin Cilic is already wearing the expression of a man who knows he has a tough shift ahead of him. Cilic clubs another forehand long for 0-15 and, after being handed a point by a wayward Djokovic forehand, soon finds himself back in his seat without a sniff of a break.
Novak asks the umpire if the floodlights are going to be switched on soon. I'd have thought his coach Boris Becker - wearing a luminous orange t-shirt - is already providing enough light to illuminate Ashe.
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Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
"This is not the best match-up for Cilic. He's got the game to beat Djokovic, but Djokovic just does everything a little bit better. He has to try and tee off to beat someone like Djokovic, but sustaining that is pretty tough to do."
Djokovic breaks
*Djokovic 2-0 Cilic
EPACopyright: EPA
Right then Marin - what has your service game got to offer? Not much initially, although that is more to do with Djokovic's fine retuning than anything else. Djokovic, decked out in a Birmingham Cityesque blue polo shirt with white collar, scrambles to force Cilic into a weak volley into the net from point-blank range then tees up a triple break point.
One goes begging as Djokovic is unable to return a deep forehand from the baseline. Then the Serb sees another disappear into the net. But he is not to be denied, a long rally ending in the top seed's favour when Cilic goes long down the line.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic has got to go for it. He can't be intimidated by Novak's groundstrokes, he can't be afraid to come in."
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Djokovic 1-0 Cilic*
Here we go. Djokovic has the hour of serving first - and earns a quick hold.
A 102mph second serve out wide sets the tone from the top seed, Cilic unable to control a wild forehand return. The Croatian hammers another forehand wide, before Djokovic bangs down another hot second serve as Cilic backhands into the net.
Then, a blistering ace from Djokovic seals the deal. Impressive.
* denotes next server
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Djokovic v Cilic (22:00 BST)
BBCCopyright: BBC
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Serena is so reliant on her athleticism, and I think her coach is a little bit at fault. She had no plan B and plan C. You can bet that Djokovic and Federer and Wawrinka have at least three gameplans."
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Djokovic v Cilic
"One minute," growls the umpire. Both Djokovic and Cilic - who has smashed down more aces than anyone else at the tournament - hammer a few serves across the net before retaking their seats. Almost showtime....
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BBC Radio 5 Live Sports Extra
Novak Djokovic on Serena Williams: "It's a sport, it happens. She is a player who expects a lot from herself, but sometimes it is not your day.
On his match: "This surface suits Marin and obviously he will step out and be aggressive."
Second round: Andreas Haider-Maurer (Austria) 6-4 6-1 6-2
First round: Joao Souza (Brazil) 6-1 6-1 6-1
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Djokovic v Cilic
Here we go. The players have arrived on Ashe, with Marin Cilic walking out first. A warm round of applause greets the Croatian before a bigger roar welcomes Novak Djokovic. Both players stick an arm around each at the net as the bring out their best smiles for the snappers. The sound man fails miserable at the coin toss - my straining ears think they heard Cilic win the toss...
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Djokovic v Cilic
BBCCopyright: BBC
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Meanwhile, the ever-cool Roger Federer strolls into Flushing Meadows as he clambers out of a dark-windowed people carrier. Little fanfare as the 17-time Slam champion slowly walks in - dipping into his pocket to pull out his accreditation.
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Djokovic v Cilic
Television pictures show us an aerial view of the sun setting over the Big Apple. Lovely stuff. But we'd rather be sat in Salford - honestly. Hopefully we will soon see images of Djokovic and Cilic striding out onto Ashe rather than the Gotham skyline....
Game, set and match
Paes/Hingis 6-4 3-6 10-7 Mattek-Sands/Querrey
ReutersCopyright: Reuters
While a murmur of anticipation rumbles around the cavernous Arthur Ashe Stadium ahead of Djokovic v Cilic, the noise volume over on Louis Armstrong Stadium is considerably higher.
Because there we have just seen Martina Hingis - the Swiss comeback queen - continue her remarkable reinvention as a doubles specialist in the mixed doubles alongside Leander Paes.
Hingis and Paes have beaten American pair Bethanie Mattek-Sands and Sam Querrey in the final, making them the first team since 1969 to win three Grand Slam titles in the same year.
Tale of the tape
Djokovic v Cilic (22:00 BST)
BBCCopyright: BBC
'A state of shock'
Piers Newbery
BBC Sport at Flushing Meadows
"With Djokovic and Cilic preparing to emerge from the locker room for one of the biggest matches of their year, even career, it is fair to say they will have to come up with something pretty special to garner much attention. Flushing Meadows remains in a state of shock after Roberta Vinci, currently beaming her way through a lengthy press conference, beat Serena Williams, currently enduring the Friday afternoon New York traffic. 'This is monumental,' former champion Tracey Austin tells BBC Sport. 'It's a shocker. This is one of the biggest upsets in the history of tennis, because of what was on the line.'"
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How much of a shock was Serena Williams' earlier defeat by unseeded Italian Roberta Vinci? Vinci's admission that she never dreamed that she would beat the top seed tells you.
And former American player Jeff Tarango - now working for our colleagues on BBC Radio 5 live sports extra - reckons it is "one of the biggest sporting upsets ever". Now, our Jeff is a man not afraid of a hyperbolic statement, but it has got us thinking. What is THE greatest sporting upset?
You know the drill. Tweet #bbctennis or text 81111. Come on, let's be 'aving you!
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Recovered from our first instalment of gripping tennis yet? Good. And if you are only just arriving to the party then you've missed one heck of a shocker. No, your ex-partner hasn't turned up with a new squeeze - hot favourite Serena Williams has been dumped out of the women's semi-finals.
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How's the rest of the night going to pan out? We're about to find out. First through the door at Arthur Ashe Stadium - in about 10 minutes - are Novak Djokovic and Marin Cilic. And the all-Swiss battle between Roger Federer and Stan Wawrinka follows that match.
Good job it is a Friday night - you've got no excuse not to stay up.
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Four Grand Slam winners. Two spots in the men's singles final. It doesn't take a mathematical genius to work out that equation.
Either world number one Novak Djokovic or defending champion Marin Cilic will be heading home tonight.
And then they might see either Roger Federer, the 17-time Slam maestro, or French Open champion Stan Wawrinka going through security at JFK Airport in the morning.
Welcome to Semi-final Day Part II.
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The Fab Four are going through their final preparations before heading on stage at Flushing Meadows. Tightening their strings, limbering up, perhaps stretching their vocal chords.
It was 50 years ago today (almost) that John, Paul, George and Ringo taught New York how to play.
But tonight, just a thumping volley across Flushing Meadows from the now-demolished Shea Stadium where The Beatles played their biggest and most iconic gig, four more blokes are hoping to whip the American crowd into a ear-splitting frenzy. And there is not a mop-top in sight.
Ladies and gentleman, here is tennis' very own Fab Four...Novak, Marin, Stan and Roger.
Veni, vidi, Vinci
Getty ImagesCopyright: Getty Images
Against the odds, Italy's Roberta Vinci came saw and conquered against the world number one and 21-time Grand Slam champion Serena Williams.
Can the men top that? They'll have to go some, but make sure you join us for Novak Djokovic v Marin Cilic and Roger Federer v Stan Wawrinka at 21:45 BST. Until then, arrivaderci.
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So, a 33-year-old faces a 32-year-old in the women's final, and we're about to have the mixed doubles final, featuring 34-year-old Martina Hingis and 42-year-old Leander Paes.
Is there any hope for us young folk?
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Quiet please, ladies and gentleman. The United States' tennis-loving first lady, Michelle Obama, has spoken...
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Who's your money on for tomorrow then? Two first-time Grand Slam finalists, the world number 26 against the world number 43.
Pennetta will probably start as favourite, and she leads the head-to-head 5-4. But who would bet against Vinci in this form?
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James Gallagher: Vinci's an instant star after that match and post-match interview!. Sorry for Serena, but that's entertainment.
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Curt would be a generous description of that press conference from Serena Williams. She's clearly eager to get it over and done with. But to her credit, she remains professional with the media.
Player reaction
Williams 6-2 4-6 4-6 Vinci
Serena Williams: "She played out of her mind. I don't think I played that bad - made a few more unforced errors - but she played really well.
"I don't feel pressure, never feel pressure and never felt that pressure to win here. I said that from the beginning.
"I made a couple of tight shots - about two - but that is normal in any match for me."
ReutersCopyright: Reuters
'I don't want to talk about it'
Serena's doing her press conference now.
"I don’t want to talk about how disappointing this is for me," she says. "If you have any other questions I’m open to that."
Full quotes to come...
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David Law
BBC commentator
"Roberta Vinci beating Serena Williams is one of the biggest upsets the sport has seen, perhaps any sport has seen."
ReutersCopyright: Reuters
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Jeff Tarango
Former professional tennis player on 5 live sports extra
For the first time ever, the women's final sold out before the men's final because of Serena aiming to win the calendar Grand Slam. It is a shame that Serena is not in it, but also a breath of fresh air that Vinci is there. However, I think a few ticket holders will be disappointed not to be seeing Serena trying to create history.
'Frozen Serena'
Chris Evert on ESPN: "I saw a frozen Serena Williams. I saw a paralysed Serena Williams. She succumbed to the nerves. She is human."
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Top day for Fabio...the other finalist, Flavia Pennetta, is his girlfriend.
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It's Van Gool: We all love a great champion like Serena but sometimes it's great to see a true underdog triumph.
Dennis Ethan: That's why I love tennis. Every point counts! Congrats Vinci!
EPACopyright: EPA
Forza Italia
And quite incredibly, that means we will have an all-Italian women's singles final. Between Flavia Pennetta, the world number 26, and Roberta Vinci, the world number 43.
Unbelievable...
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Jeff Tarango
Former professional tennis player on 5 live sports extra
"You can look back on this in 10 years - and say this is one of the biggest upsets in sporting history, especially with Serena going for the calendar Grand Slam. I can't recall seeing, in the history of women's tennis, the first and second seeds losing in the semi-finals of a Grand Slam."
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Roberta Vinci is absolutely brilliant. Mad as a box of frogs, but brilliant. Get this woman on the late-night chat shows. Heck, get her her own chat show!
Player reaction
Williams 6-2 4-6 4-6 Vinci
Roberta Vinci: "I'm sorry for the American people, for Serena, the Grand Slam, everything...but today is my day.
"I'm proud of myself, my fight and my game. I'd like to say thank you to my coach and my team - grazie!
"I will enjoy this moment today - and then tomorrow we will see."
APCopyright: AP
Player reaction
Williams 6-2 4-6 4-6 Vinci
Roberta Vinci: "When I woke up this morning I said to myself I have a semi-final, just enjoy it, don't think about Serena. I didn't expect to win - but I won!
"I said in my mind 'put the ball on the court and run. And don't think about Serena on the other side of the court'."
Player reaction
Williams 6-2 4-6 4-6 Vinci
Roberta Vinci: "This is an incredible moment for me - amazing. It is like a dream. I'm in the final, I beat Serena...phew.
"So many things are in my mind. It was an incredible match, I lost the first set, and tried to stay in every point. I tried to stay focused and not think about Serena. It is the best moment of my life."
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"What gave you the belief that this moment was possible?" Roberta Vinci is asked.
"No," she replies.
Full quotes (from what I must say is an endearingly bonkers post-match interview) to come...
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BBC Radio 5 Live Sports Extra
Quote Message: Vinci has never been to a Grand Slam semi-final before, let alone a Grand Slam final.It was a virtuoso masterclass from the Italian - Serena Williams had no answer. New York is in shock. from David Law BBC Radio 5 live sports extra commentator
Vinci has never been to a Grand Slam semi-final before, let alone a Grand Slam final.It was a virtuoso masterclass from the Italian - Serena Williams had no answer. New York is in shock.
Game, set and match
Williams 6-2 4-6 4-6 Vinci
Getty ImagesCopyright: Getty Images
That is utterly extraordinary. I think we may just have seen the greatest sporting upset of the 21st century. Roberta Vinci is in tears.
The Italian served out nervelessly for the biggest win of her career, taking the final point with a magnificent pick up off her toes. The Serena Slam is over.
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Serena sends another easy volley into the net. Three match points for Vinci...
APCopyright: AP
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Serena gets a gimme second serve on the first point, but swats it into the net. Then Vinci plays a lovely volley to bring up 30-0. She's two points away...
Williams 6-2 4-6 4-5 Vinci*
Serena is looking so tentative out here as the dream of the Grand Slam slips away. A leaden-footed forehand finds the net, and she's 0-15 down. But she's not a champion for nothing - she reaches into the locker and pulls out two aces to take her to 40-15. She cleans up the game with an emphatic smash. Drake Watch: pacing nervously. Vinci has a long changeover to think about serving for the match. Against Serena Williams...
APCopyright: AP
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BBC Radio 5 Live Sports Extra
Quote Message: The American crowd can't believe this. There a few rows of people in Vinci's box going absolutely ballistic. But everyone else in this 20,000-plus crowd are about to have the biggest balloon popped. from David Law BBC Radio 5 live sports extra commmentator
The American crowd can't believe this. There a few rows of people in Vinci's box going absolutely ballistic. But everyone else in this 20,000-plus crowd are about to have the biggest balloon popped.
*Williams 6-2 4-6 3-5 Vinci
You know what we need right now? 'Wannabe' by the Spice Girls. Thankfully the DJ at Flushing Meadows obliges with a burst of the 90s classic over the PA system. Now, can Vinci hang on to her advantage?
Serena gets to 15-30 with a nerveless high putaway. Vinci has gone too defensive here - she's throwing up too many lobs, and the American smashes another one away to bring up two break points. Serena sends the first one long, she's in control of the second rally - but she steers the ball into the tramlines!
Another tight backhand goes into the net, and Vinci has game point. And she throws in a double! Unbelievable. Serena, though, has lost all confidence on the length of her groundstrokes - another one sails over the baseline to give Vinci a second opportunity. And she takes it when Serena fires wide! She's one game away...
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Serena's game has no firm structure and she hasn't figured out a plan B - she is just relying on being Serena out there. Serena needed to regroup - I think that was a good time to call the trainer. She needs to play some smart tennis to win.
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BBC Radio 5 Live Sports Extra
Quote Message: This is an unbelievable atmosphere inside the Arthur Ashe Stadium. Roberta Vinci doesn't care a fig for history - she wants to create her own history. What a story this is. from David Law BBC Radio 5 live sports extra commentator
This is an unbelievable atmosphere inside the Arthur Ashe Stadium. Roberta Vinci doesn't care a fig for history - she wants to create her own history. What a story this is.
Live Reporting
Jonathan Jurejko and James Gheerbrant
All times stated are UK
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Goodbye
Robotic, indefatigable, top seed Novak Djokovic?
Or the smooth, majestic, 17-time Grand Slam winner Roger Federer?
Anyone dare to call Sunday's US Open final? Nope, me neither. Although I'll let you into a not-so-secret bit of info - Federer leads 21-20 in the head-to-head against his great rival.
Make any difference? Probably not. But it gives you a little something to occupy your mind when thinking about the outcome.
Right it is time for us to say goodbye. We will be back tomorrow for the women's final and of course will return on Sunday. See you then!
Player reaction
Wawrinka 4-6 3-6 1-6 Federer
Roger Federer: "Novak has had a tremendous year, there's always a lot on the line when we play. He's the best mover on the hard courts, he's tough mentally, but I like that challenge and I'll be ready for it.
"Serena has done unbelievably well, maybe it just wasn't meant to be. We're lucky that she's still playing tennis."
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Liam Walton: Federer is just unbelievable. Even at the age of 34, he makes it look so easy! Class is permanent.
Player reaction
Wawrinka 4-6 3-6 1-6 Federer
Roger Federer: "Obviously I am very happy. It's been a great tournament so far - I have tried so hard over the last six years to the get back into the final, and tonight it worked.
"I'm serving very well, I'm going for my shots, I'm playing positive tennis. I practised for years in front of nobody, I'm not going to throw away moments like this."
Federer reaches US Open final
Wawrinka 4-6 3-6 1-6 Federer
Stan Wawrinka trudges off court looking slightly shellshocked - he has been hit by the Fed Express. Rather like Marin Cilic before him, he didn't have the opportunity to lay a glove on his illustrious opponent. The two Swiss men warmly embrace at the net - I don't think I could be so gracious to someone who has just thumped me in front of 20,000 people.
Stan will move up to fourth in the world rankings after this tournament. Scant consolation.
Federer reaches US Open final
Wawrinka 4-6 3-6 1-6 Federer
That routine win - which has taken just 92 minutes - means second seed Roger Federer will meet top seed Novak Djokovic in Sunday's final. I think those two are quite familiar with each other....
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Russell Fuller
BBC tennis correspondent on Radio 5 live Sports Extra
"You run out of superlatives. There is nothing that Stan Wawrinka can do to stop the Roger Federer juggernaut rolling artistically onward."
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"The fans are on their feet clapping as if Federer has just finished a concerto."
Game, set and match - Federer
Wawrinka 4-6 3-6 1-6 Federer
Wawrinka threatens to make Federer wait at 15-30, but then again has no answer to Federer. That brings up match point - and a huge roar of anticipation from the Ashe crowd. Wait - Stan isn't going without a fight. A trademark backhand winner down the line makes Roger hold on.
But not for long, Federer tees up a second match point - and blasts an ace down the middle. Job done.
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Wawrinka 4-6 3-6 1-5 Federer*
So here we go. With less than 90 minutes on the clock, Roger Federer is serving for the match....
Federer breaks
Wawrinka 4-6 3-6 1-5 Federer*
We think we've cracked what is making Roger Federer so difficult for Stan Wawrinka to get near. Not the dreamy forehands or sensational serves. Not the precision punches or his anticipation. Nope, it is the eye-squinting colour of neon pink trainers. Poor old Stan's sight is being dazzled.
Of course we jest - Federer has been simply off the scale. As illustrated as he racks up another break point. Wawrinka tries every plan of attack that he has, but Federer's defence holds firm as they trade blows in a long rally. And it is the fifth seed who crumbles first, slapping a frustrated forehand into the net.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Federer is really in the zone. He looks really mentally fresh. He's getting more sleep now, because his kids have grown up a little."
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Russell Fuller
BBC tennis correspondent on Radio 5 live Sports Extra
"It's almost like Federer is in a race with Novak Djokovic. This goes down as more impressive. It's a remarkable demolition."
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*Wawrinka 4-6 3-6 1-4 Federer
Following up the break of serve with a booming ace is exactly what Federer could have hoped for. And that's exactly what he gets. That sets the platform for a comfortable hold - save for a stray backhand for 40-15 - and leaves Federer two games from yet another US Open final.
Federer breaks
Wawrinka 4-6 3-6 1-3 Federer*
How important could this point be? A match winner for Federer? Quite possibly. The game is delicately poised at 30-30 as the pair become embroiled in a baseline shootout. Duh duh duh...Wawrinka blinks first to hand a break point to Federer. And another unforced error from Wawrinka - this time going long - puts Fedrer on course to wrap this up quick sharp.
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*Wawrinka 4-6 3-6 1-2 Federer
Federer is purring like a cat which has just devoured a saucer of the finest cream on the planet. His smooth serve peppers the Wawrinka defence, finishing off his rival with a forehand smash.
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Wawrinka 4-6 3-6 1-1 Federer*
Solid hold from Wawrinka, allowing Federer just the one point. Unfortunately solid holds alone aren't going to stick the fifth seed in the US Open final. He needs a breakthrough....
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*Wawrinka 4-6 3-6 0-1 Federer
Thanks James. During the changeover Wawrinka would have been sat in his chair, dreaming of a morale-boosting break at the start of the third set. A rare double fault from Federer gives him a whiff of one at 40-30, but then slams the door shut on his Swiss compatriot. Stan is not the man as his usually faultless backhand crashes into the net.
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Here's Jonathan Jurejko to take you through to the conclusion...
Federer wins second set
Wawrinka 4-6 3-6 Federer*
Wawrinka is under siege. This is a man who has won two Grand Slam titles and he quite literally doesn't know what to do. Such is Federer's brilliance, he's reduced to trying impossible winners and hopelessly over-ambitious trick shots.
He balloons a forehand long to bring up 0-40 and three set points. Federer needs only one. A seventh US Open final is in sight.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
*Wawrinka 4-6 3-5 Federer
This is glorious, artistic tennis from Federer. He's going through the whole repertoire at the moment. When Wawrinka tries to put a smash into the empty court, Federer is there. When Wawrinka tries to lob him, Federer somehow scrambles back and manages to flick it disdainfully back past him. Wawrinka can't lay a glove on him.
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Russell Fuller
BBC tennis correspondent
Federer breaks
Wawrinka 4-6 3-4 Federer*
The scoreboard might be all square - but there's no doubt who is under the more pressure. A mishit from Federer forces Wawrinka back, and suddenly he's in trouble again at 0-30. Stan goes long and Federer has three break points. Wawrinka fires long again, and Federer is in charge in the second set.
*Wawrinka 4-6 3-3 Federer
The Federer serve is well and truly firing. The ball toss, the arch of the back, the rapid arm all flowing in one seamless movement - the ball more often than not kissing the corner of the service on its way past Wawrinka. If that doesn't work, saunter to the net and poke a volley past Stan. Easy peasy.
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Russell Fuller
BBC tennis correspondent on 5 live sports extra
Wawrinka 4-6 3-2 Federer*
*denotes next to serve
If Federer was a boxer, he wouldn't just have quick hands and a pretty left hook, he'd also be adept at soaking up punishment. He rides a couple of huge groundstrokes from Wawrinka and loops a big forehand winner into the corner.
Wawrinka sends a simple volley into the net and it's break point Federer. A big serve comes to Stan's rescue. Then it's another pistols-at-dawn point at the net, with Federer emerging victorious with a volleyed winner.
Another break point, but Stan closes it out with a good volley of his own, which he follows with a bellowed 'Come on!' Two big serves, and he's in the clear.
*Wawrinka 4-6 2-2 Federer
Wawrinka garnered a lot of attention during the French Open for wearing shorts that were more garish than a hippie's tablecloth, but disappointingly, he's bedecked in a crisp white pair today.
Federer rattles through another brisk game, scooting to net to punch away a couple of volleys. We remain on serve.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Wawrinka 4-6 2-1 Federer*
Federer tries to charge the serve again, but this time he finds the net. A booming backhand down the line takes Wawrinka to 40-0, and Federer coughs up the game when he nets a forehand.
*Wawrinka 4-6 1-1 Federer
Bradley Cooper is in the audience. So far today we've seen him, Sean Connery and Canadian rapper Drake, which coincidentally is the line-up for my dream dinner party.
Talking of dreams, Roger Federer's serve is pretty dreamy - he finds the corners with pinpoint accuracy for an impressive hold to love.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Wawrinka 4-6 1-0 Federer*
* denotes next to serve
Wawrinka, by the way, is yet to beat Federer on hard courts - he's 0 for 8, as the Americans say. This is a must-win set for the fourth seed.
A double-fault and a typically picturesque leaping forehand from Federer take him to 30-30, and he opens up the court masterfully to give himself a forehand down the line for break point.
Terrific response from Stan, bludgeoning an inside-out forehand into the corner. Two big serves complete the escape act, and that's a big hold.
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John McEnerney: Fed looking majestic but Stan is no slouch this hopefully will go the distance after that walkover by Novak. Federer in four.
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Sara Orchard
BBC Radio 5 live sports extra commentator
Federer wins first set
*Wawrinka 4-6 Federer
Now look, I'm a modern man, in touch with my feminine side and all that, but I'm not sure I'd be too comfortable wearing the Federer get up down the local municipal courts. White polo with pink collar and piping, shorts with pink piping, pink wristbands and pink trainers. It's...zingy.
Still, it's not doing Federer any harm out there - a slightly too aggressive Wawrinka sends some potent groundstrokes over the baseline and into the net to bring up two set points. Another forehand flies long from Stan, and that's the set.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Wawrinka 4-5 Federer*
* denotes next to serve
One thing Federer has been brilliant at over the years is sending the ball about a gnat's width over the net with the velocity of a speeding asteroid - Wawrinka comes to net to dispatch a volley but suddenly finds the ball at his bootlaces and can't get it over the net. 30-30.
Stan again targets Federer, sending a smash straight at him to bring up 40-30, and he closes the deal. Fed will serve for it.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
*Wawrinka 3-5 Federer
Now, I know the Swiss are a peace-loving nation. And yes, yes, these two are great pals, yadda yadda. But if my imagination doesn't deceive me, Stan is going for Roger here. He's trying to foil Fed's sneaky tactic of rushing to net with the not-so-subtle strategy of absolutely leathering the ball at him when he gets there.
It works as he almost takes the racket out of Roger's hand, bringing up 15-30, but Federer gets himself out of trouble with three straight points.
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Wawrinka 3-4 Federer*
Oh my word. Wawrinka looks to be cruising at 40-15, but he sends a forehand long. Can Federer get to deuce? Wawrinka absolutely nails a smash at 40-30, but Federer, inescapable as time, is there, somehow, and absolutely pings it right off the strings about an inch over the net. Stan is equal to it though and nonchalantly knifes the volley into the open court. That is what Alan Partridge would call liquid tennis.
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Jeff Tarango
Former professional tennis player
*Wawrinka 2-4 Federer
Federer's usual gossamer touch deserts him at the net as a drop volley sits up for Wawrinka to smack a passing winner past him, and suddenly Stan has 0-40 and three break points.
Federer saves the first two with an ace and a putaway, and he fends off the third with a display of real cojones - following a second serve into the net and painting the sideline with a volley. He closes out a Houdini-esque hold with an ace.
Wawrinka 2-3 Federer*
* denotes next to serve
That'll make Stan feel better - absolutely torching a backhand winner past Fed to get to 40-0. That one left scorchmarks on the court. Federer then dumps one into the net and Wawrinka remains in touch.
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Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
*Wawrinka 1-3 Federer
Federer may be 34, but there's still some elastic in that serving arm - the ball is clearing the spectators in the first row as it bounces past the flailing Wawrinka. A couple of howitzer deliveries help Federer to a love hold.
Federer breaks
Wawrinka 1-2 Federer*
Now then, here's the Roger Federer sneak attack that we've been hearing so much about. In case you haven't keeping your ear to the tennis grapevine, Fed has caused a few ripples by charging into the net to take his opponent's serve halfway up the court. It fails the first time, by on the next point it works and Wawrinka nets.
The tactic clearly unsettles Wawrinka and he pings a forehand off the tape and into the tramlines to bring up break point. Wawrinka sends a forehand long, and it's first blood to Federer.
*Wawrinka 1-1 Federer
On 5 live, Jill Craybas reckons that you can tell by the way Stan uses his walk, he's a US Open contender, no time to talk. Or words to that effect. He certainly carries a bit of a spring in his step.
But then again the man across the net, resplendent in pink sweatbands today, has never been known for a lack of confidence either. Federer fends off a minor hiccup at 30-30 with a good approach, but then Wawrinka stings him a crisp one-hander down at his toes. Deuce.
Fed sends one into orbit off the frame, and suddenly he's staring down the barrel of a break point. Stan shanks the return, and then sees an ace whizz past him at nostril height. Wawrinka sends a backhand long, and Rog is on the board.
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Christopher David: Currently contemplating how long I stay up to watch this undoubted classic Federer/Wawrinka match.
Wawrinka 1-0 Federer*
* denotes next to serve
Woof. Plenty of mustard on the Wawrinka serve, and he's up and running with a simple hold.
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Here we go. It's Wawrinka to serve first...
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Swiss spat
Roger Federer v Stan Wawrinka
But then again, he's got a formidable obstacle in his path: Stan Wawrinka, undoubtedly the most improved player on tour over the past couple of years.
These two have had a complicated relationship. For many years, they were great friends, enjoying some great times together, including winning gold at the 2008 Olympics.
But the Swiss neutrality was rather soured last year when Federer and Wawrinka had a spat at the ATP Tour Finals, apparently sparked by Mrs Federer calling Wawrinka a "crybaby".
The two of them thrashed it out in the locker room, we're told. But who knows, if this one goes the distance, is it too much to hope it could get a little bit spicy?
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Fabulous Fed
Roger Federer v Stan Wawrinka
Let's begin with a consideration of Roger Federer - a man who has used up all the superlatives in the dictionary, and all the space on his mantlepiece over a glittering 16-year career.
You keep waiting for Federer to lose it. To enter a terminal decline. But no, at 34, he seems to be playing better than ever. Heck, he's won his last 35 sets. Could he finally clinch his 18th Grand Slam? You wouldn't bet against it...
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Thank you JJ. Well, what a strange day it's been at Flushing Meadows. Simona Halep taken to the cleaners. Serena Williams losing from a set up against the world number 43. And now, the defending men's champion booted out the back door on the back of the most one-sided semi-final in the Open era.
What surprises might Federer v Wawrinka have in store? We wait to find out...
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Federer v Wawrinka
So the identity of one US Open men's finalist is known. But who is the top seed going to face? One thing is certain - it will be a Swiss fella.
Good job that the Alpine nation is well-known for being a 'neutral' country as two of their stars scrap for a place in the Flushing Meadows final.
Here's my team-mate James Gheerbrant to talk you through all things Swiss....
Djokovic reaches US Open final
Djokovic 6-0 6-1 6-2 Cilic
As if the scoreline doesn't already tell you everything, here are a few more numbers to make Marin Cilic wince. The key stat being that Cilic made 37 unforced errors compared to Djokovic's 13. And the top seed won 87 points in total, dwarfing the 39 earned by Cilic.
Player reaction
Novak Djokovic: "I'm very proud to have reached all four Grand Slam finals. I haven't been very successful in the finals of the US Open - I have won one and lost four. But I can promise I will give it my best. I will definitely get ready to play against a Swiss player!
"Serena is a great champion, she is somebody I respect a lot, it wasn't to be today but it takes nothing away from what she has achieved in her career."
Player reaction
Djokovic 6-0 6-1 6-2 Cilic
Novak Djokovic: "Marin was carrying an injury, he was courageous to come out and finish the match, so applause to him.
"I came out with good focus and good intensity and executed the gameplan."
Djokovic reaches US Open final
Djokovic 6-0 6-1 6-2 Cilic
Novak Djokovic is grinning like a Cheshire Cat as he addresses the Arthur Ashe Stadium after that routine win. He admits he is hoping to rectify his poor record in the Flushing Meadows final - winning one and losing four - on Sunday. There he will face one of Swiss pair Roger Federer or Stan Wawrinka who are next on the star-studded US Open bill.
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Jill Craybas
Former world number 39 on BBC Radio 5 live Sports Extra
"It's a shame - Cilic obviously isn't feeling 100%. He fought his hardest, but he couldn't move today, he couldn't give his best."
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Djokovic 6-0 6-1 6-2 Cilic
It is hard not to feel some sympathy for Marin Cilic. Novak Djokovic made him look like a club player rather than a Grand Slam winner. Although, as Novak graciously points out in his on-court interview, the ninth seed has been struggling with an ankle injury over the past couple of matches. Did that have a part to play in Cilic's no-show? Probably - sure we will find out more about that a little later on.
Game, set and match - Djokovic
Djokovic 6-0 6-1 6-2 Cilic
Stunning stuff. Novak Djokovic brings an overhand backhand smash to the party, giving himself three match points. Second serve....Cilic returns....Novak plants a forehand into the net. One down. But Cilic coughs up the second, a long baseline rally ending when the Croatian clunks a forehand long. He couldn't wait to escape from Ashe....
Djokovic breaks
Djokovic 6-0 6-1 5-2 Cilic*
Don't you hate those people who say 'I told you so'? Well, I told you so. Novak Djokovic does not look like he needs two service games to see of Marin Cilic. More errors from the Croatian gift three break points to Djokovic, who snaffles the first one. The record for the least number of games lost in a US Open semi-final? Four. And that came in 2001 when Lleyton Hewitt beat Yevgeny Kafelnikov...
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Djokovic 6-0 6-1 4-2 Cilic*
Novak Djokovic is two service games away from his sixth US Open final - and it might not even take him that long. Cilic takes the first point in game eight of the third set, only for the Serb to wipe that out with an ace before going on to clinch the hold without further damage.
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David Law
BBC Radio 5 live Sports Extra commentator
"Cilic is giving everything he's got. He's not short-changing the fans at all. But they are watching a masterclass from Djokovic."
Djokovic breaks
*Djokovic 6-0 6-1 3-2 Cilic
Beware the wounded world number one. Cilic's break in the last game was only the eighth time that Djokovic has not held his serve in this tournament - and he didn't like it. He goes on the attack against the Croatian, teeing up two break points and nabbing the first one. As you were...
Cilic breaks
Djokovic 6-0 6-1 2-2 Cilic*
Cilic glances up towards the scoreboard at 30-15 - don't do it, Marin. He looks dazed and confused - rather like a man who has been released into everyday society after a period of captivity.
But the stark realisation of the numbers do seem to jolt him into life. A brilliant forehand winner helps him tee up a break point. Yes, you have read that right - Marin Cilic has a break point. And he takes it!
High-quality stuff from the defending US Open champion, whose neat dropshot is even too much for Djokovic to rescue. A bald gentleman wearing a Croatian football shirt and red and white paint on said follically-challenged cranium claps heartily - as does the rest of Ashe.
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Jill Craybas
Former world number 39 on BBC Radio 5 live Sports Extra
"That was a better game from Cilic. He's still struggling, but at least he tried to play the right style of tennis: big serve and big forehand."
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*Djokovic 6-0 6-1 2-1 Cilic
Marin Cilic manages to salvage some pride with his best service game of the evening. And he even manages to cook up a double fault in this. The Croatian cruises into a 40-0 advantage with an ace, has a little wobble with a couple of shocking serves, then regains his composure to win the game with a crunching forehand down the line.
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David Law
BBC Radio 5 live Sports Extra commentator
"In this sort of form, Novak Djokovic is going to take some stopping at this US Open."
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Djokovic 6-0 6-1 2-0 Cilic*
Move along, nothing to see here. Apart from more Djokovic brilliance that is. The top seed holds out to love again, sealing the game with a scrumptious lob that a scrabbling Cilic manages to reach but can't stick back over the net.
Djokovic breaks
*Djokovic 6-0 6-1 1-0 Cilic
Anyone giving Cilic any chance of winning a set? The most optimistic - or sympathetic - fans might have done about one minute ago - not now.
The Ashe crowd try to gee up Cilic after he bangs an ace down the T for 15-30, before Djokovic curses himself for overcooking a backhand down the line. Chill out Novak, you're coasting.
Luckily Cilic is feeling charitable today, handing over a break at the first opportunity.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic should pull the plug. There's nothing Goran Ivanisevic can say to him to spark him into life."
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David Law
BBC Radio 5 live Sports Extra commentator
"You've got to give Djokovic massive credit. He is so tunnel-visioned about what he wants to do. He's a great friend of Marin Cilic but that counts for nothing."
Game and second set - Djokovic
Djokovic 6-0 6-1 Cilic
Incredible. Wonderful. Clinical. Insert any other superlative of your choice. Djokovic gives the tiniest whiff of hope to Cilic at 30-30, before snatching it out of his hands with a second ace of the match and an aggressive forehand down the line. Cilic doesn't know what day it is.
Double break for Djokovic
*Djokovic 6-0 5-1 Cilic
If this was a boxing match then the referee would be stepping in. Djokovic earns another break of the Croatian's serve - now he is serving for the second set. Cilic goes 30-15 up and then pulls out a 106mph second serve which Djokovic duly spanks a blistering crosscourt forehand. Wow. That knocks the stuffing out of Cilic, who meekly surrenders the final two points.
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Djokovic 6-0 4-1 Cilic*
Novak Djokovic is rattling through his service games quicker than a comedian goes through one-liners. But Marin Cilic isn't laughing. Djokovic generously allows Cilic a first point of the second set against his serve, only for the Croatian to repay the favour with another unforced error - a lazy forehand into the net - to seal the game in the Serb's favour.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"I think Goran Ivanisevic [Cilic's coach] might get up and walk out. I'm not sure what's going on inside his head right now - I imagine it looks like a lava fireball."
Djokovic breaks
*Djokovic 6-0 3-1 Cilic
Stop the clock! We're 42 minutes into this, ahem, contest and we see our first poor shot from Novak Djokovic. The Serb looks to the heavens as he plants a weak forehand into the net at 30-15. But soon it is Cilic grimacing again. Another break point to Djokovic when the Croatian crumbles after a long baseline rally, then another forehand unforced error gifts the first break of the second set to the world number one.
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David Law
BBC Radio 5 live Sports Extra commentator
"It's almost as if Cilic isn't in the right place for some of these shots. His footwork isn't dynamic enough."
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Djokovic 6-0 2-1 Cilic*
How would 007 get out of a scrape like this? With some smooth talking and a cunning escape plan probably. Let's hope Marin Cilic, who sees another Djokovic service game to love flash past him, has got the latter. If not then he might want to grab a quick word with Sean Connery at the changeover. A Cilic comeback? Never say never, again...
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*Djokovic 6-0 1-1 Cilic
The person who is operating the Cilic side of the scoreboard had better wake up. We need him. The Croatian finally sees a number go next to his name when Djokovic misses the target by a matter of millimetres with a crosscourt forehand. Huge cheers (maybe some ironic) from the Ashe crowd...
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Djokovic 6-0 1-0 Cilic*
Any chance of Novak Djokovic easing off? Nope. The Serb tees up another break point with some unreturnable returning, although Cilic saves that with a handy first serve which is too hot for Djokovic to handle.
But another unforced error from Cilic - a long backhand under little pressure in a routine rally - sets up a second break point for Djokovic.
Again Cilic scrambles the game back in his favour, setting up his first game point of the match - in the EIGHTH game. However, he cannot convert...
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"This is starting to look like clean up on Aisle Six."
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Djokovic 6-0 1-0 Cilic*
This is X-rated stuff from Novak Djokovic. The match needs a 'Parental Advisory' warning - it is a brutal assault on Marin Cilic. The Croatian has no answer to the Serb's service game, which is over to love in almost a blink of an eye.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic has won 15% of second-serve points, and he's only got 41% of his first serves in. You've got one player who's fresh as a daisy and another guy who's at the end of his string: that's why it's lopsided."
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David Law
BBC Radio 5 live Sports Extra commentator
"It's difficult to think how Cilic can even make a fight of this, the way it's going. There's about 20,000 people in here and they're getting nothing like a contest - you can hear a pin drop."
Game and first set - Djokovic
Djokovic 6-0 Cilic
Unbelievable stuff. Djokovic misses a second set point - but makes no mistake with a third. The top seed's movement has caused all sorts of bother for the ninth seed, who crumbles in just 24 minutes.
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Djokovic 5-0 Cilic*
Oh dear. Marin Cilic almost knocks out a ball boy with a wild swipe that is nearer the spectators' gangway than the tramline as he goes 15-0 down.
A decent first serve is a confidence booster if nothing else - as is a humdinger of a serve which flashes past Djokovic's eyeline for his first ace of the match.
But another unforced error from the baseline hands another break point to Djokovic. The Croatian pulls out a beautiful dropshot that floats over the net and touches white paint. Deuce...
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Djokovic 5-0 Cilic*
Novak Djokovic holds comfortably to 15 and then gives his face a good rub with his towel as he sits back down. I don't know why - he has hardly broken sweat. Marin Cilic, on the other hand, will be feeling rather nervous. Apparently he has only been bagelled once this year. His opponent? The bloke staring across the net from him. Novak another break of serve away from the first set....
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic isn't setting up very well. The little adjustment steps with his feet just aren't there. He's not assessing the shots well, and Novak's varying his serve, so Cilic isn't timing it that well."
Double break for Djokovic
*Djokovic 4-0 Cilic
Wow. Cilic thinks he is on the attack, whipping a forehand down the line. But Djokovic turns defence into offense quicker than Barcelona's football team. A wonderful winner down the line leaves Cilic's coach Goran Ivanisevic looking glum, although the former Slam winner's expression becomes cheerier as his man battles back to 30-30.
Cilic looks to get on top in a long rally, pounding a forehand into the corner. But Djokovic pulls a double-handed backhand out of the top drawer, forcing Cilic to volley into the net. Another break point. And then Cilic crumbles. Double fault from the ninth seed hands the game to Djokovic on a silver plate.
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Djokovic 3-0 Cilic*
Marin Cilic is already wearing the expression of a man who knows he has a tough shift ahead of him. Cilic clubs another forehand long for 0-15 and, after being handed a point by a wayward Djokovic forehand, soon finds himself back in his seat without a sniff of a break.
Novak asks the umpire if the floodlights are going to be switched on soon. I'd have thought his coach Boris Becker - wearing a luminous orange t-shirt - is already providing enough light to illuminate Ashe.
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Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
"This is not the best match-up for Cilic. He's got the game to beat Djokovic, but Djokovic just does everything a little bit better. He has to try and tee off to beat someone like Djokovic, but sustaining that is pretty tough to do."
Djokovic breaks
*Djokovic 2-0 Cilic
Right then Marin - what has your service game got to offer? Not much initially, although that is more to do with Djokovic's fine retuning than anything else. Djokovic, decked out in a Birmingham Cityesque blue polo shirt with white collar, scrambles to force Cilic into a weak volley into the net from point-blank range then tees up a triple break point.
One goes begging as Djokovic is unable to return a deep forehand from the baseline. Then the Serb sees another disappear into the net. But he is not to be denied, a long rally ending in the top seed's favour when Cilic goes long down the line.
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Cilic has got to go for it. He can't be intimidated by Novak's groundstrokes, he can't be afraid to come in."
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Djokovic 1-0 Cilic*
Here we go. Djokovic has the hour of serving first - and earns a quick hold.
A 102mph second serve out wide sets the tone from the top seed, Cilic unable to control a wild forehand return. The Croatian hammers another forehand wide, before Djokovic bangs down another hot second serve as Cilic backhands into the net.
Then, a blistering ace from Djokovic seals the deal. Impressive.
* denotes next server
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Djokovic v Cilic (22:00 BST)
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Jeff Tarango
Former professional tennis player on BBC Radio 5 live Sports Extra
"Serena is so reliant on her athleticism, and I think her coach is a little bit at fault. She had no plan B and plan C. You can bet that Djokovic and Federer and Wawrinka have at least three gameplans."
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Djokovic v Cilic
"One minute," growls the umpire. Both Djokovic and Cilic - who has smashed down more aces than anyone else at the tournament - hammer a few serves across the net before retaking their seats. Almost showtime....
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BBC Radio 5 Live Sports Extra
Novak Djokovic on Serena Williams: "It's a sport, it happens. She is a player who expects a lot from herself, but sometimes it is not your day.
On his match: "This surface suits Marin and obviously he will step out and be aggressive."
Cilic's route to the semi-finals
Djokovic v Cilic
Quarter-finals: 19 Jo-Wilfried Tsonga (France) 6-4 6-4 3-6 6-7 (7-3) 6-4
Last 16: 27 Jeremy Chardy (France) 6-3 2-6 7-6 (7-2) 6-1
Third round: Mikhail Kukushkin (Kazakhstan) 6-7 (5-7) 7-6 (7-1) 6-3 6-7 (3-7) 6-1
Second round: Evgeny Donskoy (Russia) 6-2 6-3 7-5
First round: Guido Pella (Argentina) 6-3 7-6 (7-3) 7-6 (7-3)
Djokovic's route to the semi-finals
Djokovic v Cilic
Quarter-finals: 18 Feliciano Lopez (Spain) 6-1 3-6 6-3 7-6 (7-2)
Last 16: 23 Roberto Bautista Agut (Spain) 6-3 4-6 6-4 6-3
Third round: 25 Andreas Seppi (Italy) 6-3 7-5 7-5
Second round: Andreas Haider-Maurer (Austria) 6-4 6-1 6-2
First round: Joao Souza (Brazil) 6-1 6-1 6-1
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Djokovic v Cilic
Here we go. The players have arrived on Ashe, with Marin Cilic walking out first. A warm round of applause greets the Croatian before a bigger roar welcomes Novak Djokovic. Both players stick an arm around each at the net as the bring out their best smiles for the snappers. The sound man fails miserable at the coin toss - my straining ears think they heard Cilic win the toss...
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Djokovic v Cilic
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Meanwhile, the ever-cool Roger Federer strolls into Flushing Meadows as he clambers out of a dark-windowed people carrier. Little fanfare as the 17-time Slam champion slowly walks in - dipping into his pocket to pull out his accreditation.
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Djokovic v Cilic
Television pictures show us an aerial view of the sun setting over the Big Apple. Lovely stuff. But we'd rather be sat in Salford - honestly. Hopefully we will soon see images of Djokovic and Cilic striding out onto Ashe rather than the Gotham skyline....
Game, set and match
Paes/Hingis 6-4 3-6 10-7 Mattek-Sands/Querrey
While a murmur of anticipation rumbles around the cavernous Arthur Ashe Stadium ahead of Djokovic v Cilic, the noise volume over on Louis Armstrong Stadium is considerably higher.
Because there we have just seen Martina Hingis - the Swiss comeback queen - continue her remarkable reinvention as a doubles specialist in the mixed doubles alongside Leander Paes.
Hingis and Paes have beaten American pair Bethanie Mattek-Sands and Sam Querrey in the final, making them the first team since 1969 to win three Grand Slam titles in the same year.
Tale of the tape
Djokovic v Cilic (22:00 BST)
'A state of shock'
Piers Newbery
BBC Sport at Flushing Meadows
"With Djokovic and Cilic preparing to emerge from the locker room for one of the biggest matches of their year, even career, it is fair to say they will have to come up with something pretty special to garner much attention. Flushing Meadows remains in a state of shock after Roberta Vinci, currently beaming her way through a lengthy press conference, beat Serena Williams, currently enduring the Friday afternoon New York traffic. 'This is monumental,' former champion Tracey Austin tells BBC Sport. 'It's a shocker. This is one of the biggest upsets in the history of tennis, because of what was on the line.'"
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How much of a shock was Serena Williams' earlier defeat by unseeded Italian Roberta Vinci? Vinci's admission that she never dreamed that she would beat the top seed tells you.
And former American player Jeff Tarango - now working for our colleagues on BBC Radio 5 live sports extra - reckons it is "one of the biggest sporting upsets ever". Now, our Jeff is a man not afraid of a hyperbolic statement, but it has got us thinking. What is THE greatest sporting upset?
You know the drill. Tweet #bbctennis or text 81111. Come on, let's be 'aving you!
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Recovered from our first instalment of gripping tennis yet? Good. And if you are only just arriving to the party then you've missed one heck of a shocker. No, your ex-partner hasn't turned up with a new squeeze - hot favourite Serena Williams has been dumped out of the women's semi-finals.
How's the rest of the night going to pan out? We're about to find out. First through the door at Arthur Ashe Stadium - in about 10 minutes - are Novak Djokovic and Marin Cilic. And the all-Swiss battle between Roger Federer and Stan Wawrinka follows that match.
Good job it is a Friday night - you've got no excuse not to stay up.
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Four Grand Slam winners. Two spots in the men's singles final. It doesn't take a mathematical genius to work out that equation.
Either world number one Novak Djokovic or defending champion Marin Cilic will be heading home tonight.
And then they might see either Roger Federer, the 17-time Slam maestro, or French Open champion Stan Wawrinka going through security at JFK Airport in the morning.
Welcome to Semi-final Day Part II.
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The Fab Four are going through their final preparations before heading on stage at Flushing Meadows. Tightening their strings, limbering up, perhaps stretching their vocal chords.
It was 50 years ago today (almost) that John, Paul, George and Ringo taught New York how to play.
But tonight, just a thumping volley across Flushing Meadows from the now-demolished Shea Stadium where The Beatles played their biggest and most iconic gig, four more blokes are hoping to whip the American crowd into a ear-splitting frenzy. And there is not a mop-top in sight.
Ladies and gentleman, here is tennis' very own Fab Four...Novak, Marin, Stan and Roger.
Veni, vidi, Vinci
Against the odds, Italy's Roberta Vinci came saw and conquered against the world number one and 21-time Grand Slam champion Serena Williams.
Can the men top that? They'll have to go some, but make sure you join us for Novak Djokovic v Marin Cilic and Roger Federer v Stan Wawrinka at 21:45 BST. Until then, arrivaderci.
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So, a 33-year-old faces a 32-year-old in the women's final, and we're about to have the mixed doubles final, featuring 34-year-old Martina Hingis and 42-year-old Leander Paes.
Is there any hope for us young folk?
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Quiet please, ladies and gentleman. The United States' tennis-loving first lady, Michelle Obama, has spoken...
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Who's your money on for tomorrow then? Two first-time Grand Slam finalists, the world number 26 against the world number 43.
Pennetta will probably start as favourite, and she leads the head-to-head 5-4. But who would bet against Vinci in this form?
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James Gallagher: Vinci's an instant star after that match and post-match interview!. Sorry for Serena, but that's entertainment.
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Curt would be a generous description of that press conference from Serena Williams. She's clearly eager to get it over and done with. But to her credit, she remains professional with the media.
Player reaction
Williams 6-2 4-6 4-6 Vinci
Serena Williams: "She played out of her mind. I don't think I played that bad - made a few more unforced errors - but she played really well.
"I don't feel pressure, never feel pressure and never felt that pressure to win here. I said that from the beginning.
"I made a couple of tight shots - about two - but that is normal in any match for me."
'I don't want to talk about it'
Serena's doing her press conference now.
"I don’t want to talk about how disappointing this is for me," she says. "If you have any other questions I’m open to that."
Full quotes to come...
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David Law
BBC commentator
"Roberta Vinci beating Serena Williams is one of the biggest upsets the sport has seen, perhaps any sport has seen."
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Jeff Tarango
Former professional tennis player on 5 live sports extra
For the first time ever, the women's final sold out before the men's final because of Serena aiming to win the calendar Grand Slam. It is a shame that Serena is not in it, but also a breath of fresh air that Vinci is there. However, I think a few ticket holders will be disappointed not to be seeing Serena trying to create history.
'Frozen Serena'
Chris Evert on ESPN: "I saw a frozen Serena Williams. I saw a paralysed Serena Williams. She succumbed to the nerves. She is human."
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Top day for Fabio...the other finalist, Flavia Pennetta, is his girlfriend.
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It's Van Gool: We all love a great champion like Serena but sometimes it's great to see a true underdog triumph.
Dennis Ethan: That's why I love tennis. Every point counts! Congrats Vinci!
Forza Italia
And quite incredibly, that means we will have an all-Italian women's singles final. Between Flavia Pennetta, the world number 26, and Roberta Vinci, the world number 43.
Unbelievable...
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Jeff Tarango
Former professional tennis player on 5 live sports extra
"You can look back on this in 10 years - and say this is one of the biggest upsets in sporting history, especially with Serena going for the calendar Grand Slam. I can't recall seeing, in the history of women's tennis, the first and second seeds losing in the semi-finals of a Grand Slam."
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Roberta Vinci is absolutely brilliant. Mad as a box of frogs, but brilliant. Get this woman on the late-night chat shows. Heck, get her her own chat show!
Player reaction
Williams 6-2 4-6 4-6 Vinci
Roberta Vinci: "I'm sorry for the American people, for Serena, the Grand Slam, everything...but today is my day.
"I'm proud of myself, my fight and my game. I'd like to say thank you to my coach and my team - grazie!
"I will enjoy this moment today - and then tomorrow we will see."
Player reaction
Williams 6-2 4-6 4-6 Vinci
Roberta Vinci: "When I woke up this morning I said to myself I have a semi-final, just enjoy it, don't think about Serena. I didn't expect to win - but I won!
"I said in my mind 'put the ball on the court and run. And don't think about Serena on the other side of the court'."
Player reaction
Williams 6-2 4-6 4-6 Vinci
Roberta Vinci: "This is an incredible moment for me - amazing. It is like a dream. I'm in the final, I beat Serena...phew.
"So many things are in my mind. It was an incredible match, I lost the first set, and tried to stay in every point. I tried to stay focused and not think about Serena. It is the best moment of my life."
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"What gave you the belief that this moment was possible?" Roberta Vinci is asked.
"No," she replies.
Full quotes (from what I must say is an endearingly bonkers post-match interview) to come...
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BBC Radio 5 Live Sports Extra
Game, set and match
Williams 6-2 4-6 4-6 Vinci
That is utterly extraordinary. I think we may just have seen the greatest sporting upset of the 21st century. Roberta Vinci is in tears.
The Italian served out nervelessly for the biggest win of her career, taking the final point with a magnificent pick up off her toes. The Serena Slam is over.
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Serena sends another easy volley into the net. Three match points for Vinci...
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Serena gets a gimme second serve on the first point, but swats it into the net. Then Vinci plays a lovely volley to bring up 30-0. She's two points away...
Williams 6-2 4-6 4-5 Vinci*
Serena is looking so tentative out here as the dream of the Grand Slam slips away. A leaden-footed forehand finds the net, and she's 0-15 down. But she's not a champion for nothing - she reaches into the locker and pulls out two aces to take her to 40-15. She cleans up the game with an emphatic smash. Drake Watch: pacing nervously. Vinci has a long changeover to think about serving for the match. Against Serena Williams...
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BBC Radio 5 Live Sports Extra
*Williams 6-2 4-6 3-5 Vinci
You know what we need right now? 'Wannabe' by the Spice Girls. Thankfully the DJ at Flushing Meadows obliges with a burst of the 90s classic over the PA system. Now, can Vinci hang on to her advantage?
Serena gets to 15-30 with a nerveless high putaway. Vinci has gone too defensive here - she's throwing up too many lobs, and the American smashes another one away to bring up two break points. Serena sends the first one long, she's in control of the second rally - but she steers the ball into the tramlines!
Another tight backhand goes into the net, and Vinci has game point. And she throws in a double! Unbelievable. Serena, though, has lost all confidence on the length of her groundstrokes - another one sails over the baseline to give Vinci a second opportunity. And she takes it when Serena fires wide! She's one game away...
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Jeff Tarango
Former professional tennis player on 5 live sports extra
Serena's game has no firm structure and she hasn't figured out a plan B - she is just relying on being Serena out there. Serena needed to regroup - I think that was a good time to call the trainer. She needs to play some smart tennis to win.
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BBC Radio 5 Live Sports Extra
Vinci breaks
Williams 6-2 4-6 3-4 Vinci*