ATP Finals: David Goffin stuns Roger Federer, will face Grigor Dimitrov in final
|Venue: The 02 Arena, London Dates: 12-19 November|
|Coverage: Watch live on BBC Two, Red Button, BBC Sport website and mobile app, listen on BBC Radio 5 live sports extra and follow text updates online.|
David Goffin mounted a spirited fightback to stun six-time champion Roger Federer and reach the final of the season-ending ATP Finals in London.
The Belgian seventh seed, 26, came from a set down to win 2-6 6-3 6-4, his first victory in seven attempts against the 19-time Grand Slam champion.
"I have no words. I cannot describe how I'm feeling - so much joy, so much happiness," said Goffin.
Goffin will face Bulgarian Grigor Dimitrov in Sunday's final.
The sixth seed came through 4-6 6-0 6-3 against American eighth seed Jack Sock in the second semi-final.
Dimitrov, 26, will play Goffin for the second time this week, having thrashed the Belgian 6-0 6-2 in the group stage on Wednesday.
"It's another match - I just need to keep on playing," said Dimitrov. "It's the last match of the season so, full house, and we're on."
Britain's Jamie Murray and Brazilian Bruno Soares lost 7-6 (7-2) 6-2 to defending champions Henri Kontinen and John Peers in the doubles semi-finals.
He's crushed me in practice - Federer
Federer, 36, had been a strong favourite to land his seventh title at the season finale, but will be absent from Sunday's final after suffering only his fifth defeat of 2017.
The Swiss can reflect on a remarkable year in which he has won two more major titles, among 52 match victories, but it is six years since he last won the ATP Finals.
"It's a bit disappointing for me because it's indoors, it's a court I like to play on, but I had my chances and missed them," said Federer.
"When he had them, he was very committed. I think that was the difference.
"He's crushed me too many times in practice to not also do it once in a match situation."
It was my day - Goffin
Federer went into the semi-final with a 6-0 record against Goffin, whose resistance appeared to have been broken after only seven minutes.
Goffin battled gamely to cling on in his opening service game but Federer took it on the fifth break point and went on to dominate the set.
Two rasping backhand winners down the line helped the Swiss to a second break at 4-1 and the set was wrapped up in little over half an hour.
The match turned early in the second set, when Goffin swung a cross-court forehand into space vacated by Federer to edge 2-0 ahead.
What at first appeared to be an exercise in damage limitation grew into an increasingly potent threat as Goffin's serve subdued Federer, who fired a forehand long on his only break point in the set.
When Goffin broke in game three of the decider, helped by a beautiful backhand up the line, his belief spread to the 17,000 spectators, thrilled by this unexpectedly tight contest.
A surprisingly flat Federer could not muster another challenge as Goffin served out in style to reach the biggest final of his career and guarantee a new champion on Sunday night.
"I'm so happy to play the match I played. It was such a special moment," said Goffin.
"Honestly, I don't know [what worked]. It was just the feeling of the day. I was a little bit nervous when I started the match but I started to feel the ball really well. The serve was there right to the end. It was my day."
My belief was really good today - Dimitrov
Roared on by the large Bulgarian contingent inside the O2 Arena, Dimitrov just about found a way past the in-form - if unpredictable - Sock.
Having failed to convert four match points in his last meeting with Sock, there were obvious nerves as three more chances to clinch victory passed him by before he finally sealed it.
Dimitrov could have made shorter work of it had he built on an early 3-0 lead, but Sock's huge forehand brought him six out of seven games to clinch the opening set.
The American's game then faded spectacularly and Dimitrov rolled through six straight games to level, setting up a decider that saw the two men test each other's nerve to the limit.
"That last game took a lot out of me," said Dimitrov.
"Jack is an unbelievable player. That forehand gives me so much trouble, I'm not going to lie. He was playing so well but my belief was really good today."
BBC tennis correspondent Russell Fuller
The turnaround in Goffin's fortunes has been remarkable.
Yes, he beat Rafael Nadal in his opening match, but he was listless and won only two games in his following match against Grigor Dimitrov.
Since then he has beaten the world number four Dominic Thiem and now Federer, with a super-aggressive performance - and all this as he nurses a knee problem and contemplates playing for his country in next week's Davis Cup Final.
Federer has not been at his absolute best this week, and in this semi-final looked like a man in need of a break after an exhilarating season.