|Betfred World Snooker Championship|
|Venue: Crucible Theatre, Sheffield Dates: 20 April-6 May|
|Coverage: Watch live on BBC One, BBC Two, Red Button, iPlayer, Connected TV, BBC Sport website and BBC Sport app.|
Amateur James Cahill pulled off the biggest shock in Crucible history as he completed an astonishing 10-8 first-round win over five-time champion Ronnie O'Sullivan.
O'Sullivan trailed 5-4 overnight and the increasingly rattled world number one slipped 8-5 behind, missing countless simple chances against the 23-year-old qualifier.
A jaded-looking O'Sullivan then somehow found some form, scoring breaks of 104 and 89 to level.
But Cahill, who does not even have a world ranking and is the first-ever amateur to make it through qualifying to play at the Crucible, showed remarkable composure to get over the line.
O'Sullivan was set to go 9-8 ahead but missed a relatively simple final pink to allow Cahill the chance to clear up.
And the Blackpool potter made sure of his place in round two with a fine clearance of 53 in the final frame.
"I could barely stand up at the end. I am not really sure what to say," he told BBC Sport.
"I scored a good pressure 70 to go 6-5 up and after that I felt like he was the one under pressure. He didn't want to lose to me.
"I have always believed in myself and that I can beat anyone on my day. I want to show what I can do now."
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He earns £30,000 for reaching the second round, the biggest payday of his career, and will face Scotland's Stephen Maguire next.
After bowing out in the opening round for the first time since 2003, O'Sullivan said a combination of illness and his recurring insomnia had contributed to his sluggish performance.
"I felt horrendous. I was struggling to stay awake," said the 43-year-old.
"I haven't felt great for a few weeks and I have not slept brilliantly the past couple of nights."
|Big first-round shocks at the Crucible|
|Tony Knowles 10-1 Steve Davis (1982)|
|Stuart Bingham 10-7 Stephen Hendry (2000)|
|David Gray 10-9 Ronnie O'Sullivan (2000)|
|Michael Wasley 10-9 Ding Junhui (2014)|
|Rory McLeod 10-8 Judd Trump (2017)|
Rejuvenated Cahill puts career back on track
Cahill is the son of former leading women's player Maria Cahill (nee Tart) and developed his love of the game at the snooker club his mother ran in Blackpool.
His parents took him out of school at 15 and paid for a tutor so he could travel to tournaments and their decision looked to have paid off as his career showed early promise.
His most notable victory came at the 2014 UK Championship when, aged 18, he beat the in-form Ding Junhui on his way to the fourth round, but he then had a barren run and struggled to earn enough prize money to carry on.
He lost his professional status in 2017 but decided to give it another go and has won back his tour card from next season.
Earlier this season he beat then world number one Mark Selby in the first round of the UK Championship.
He backed up that impressive performance by coming through three qualifying matches and has now beaten the player considered the greatest of all time, and one who has won five titles and passed 1,000 career centuries during a superb season.
Cahill was not even born when O'Sullivan made his debut at the World Championship in 1993 and his career earnings of £80,000 before qualifying began are dwarfed by the estimated £10m the Rocket has pocketed in his stellar career.
O'Sullivan not at 100%
Pre-tournament O'Sullivan had talked about the need to win this year's event if he is to stand a chance of equalling Stephen Hendry's seven world titles.
But he appeared to rush against Cahill, taking an average of about 15 seconds per shot, and was often too casual - telling BBC Sport afterwards that his "limbs felt heavy" and he "had no energy".
"You have to come here physically and mentally well. If you are not 100% it will make it harder. I tried to hang in there and get through and have a few days off.
"He did well. He held himself together. It's been a very successful season for me, but it wasn't meant to be."
Defeat means the 36-time ranking event winner has not reached the World Championship quarter-finals since 2014, while this is the fourth time he has lost in the first round at snooker's showpiece event in his 27 visits.
His exit leaves Australia's Neil Robertson and England's Judd Trump as the favourites to lift the title.
- Watch live coverage of day four at the Crucible
- Tournament schedule, scores and results
- How to watch the World Championship on the BBC
Six-time world champion Steve Davis:
What a fantastic performance by James Cahill. The way he cleared those balls up under significant pressure - because they were there to be taken - sometimes that makes it an even harder job.
Knowing what was probably going through his mind about how big a deal it would be, to still hold himself together to pot that last red, and then clear what was a normal set of colours under that pressure, is absolutely fantastic and he must be absolutely delighted.
1997 world champion Ken Doherty:
This is probably the biggest [ever shock at the Crucible].
The fact James Cahill is still an amateur, the first amateur to ever play at the Crucible, and he's beaten probably the greatest player that's ever played this game, and looked so calm.
He played with a smile on his face, didn't look like he was nervous and looked like he was loving every minute of it.