World number one Ronnie O'Sullivan on Tuesday crashed out of the World Championship in the first round after losing 10-8 to amateur James Cahill.
Here, Press Association Sport looks at some of the other biggest shocks in snooker history.
Stuart Bingham v Stephen Hendry (2000)
Seven-time champion Hendry was expected to get the latest defence of his title off to a straightforward start against world number 97 Bingham, who was making his Crucible debut after coming through the qualifiers. Hendry led 5-4 after the opening session but Bingham won five of the next six frames and produced a break of 87 to send Hendry crashing out on the opening day.
Tony Knowles v Steve Davis (1982)
Davis had won the first of his six world titles the previous year and was an odds-on favourite to defend his crown. Bolton qualifier Knowles had other ideas however, racing into an 8-1 overnight lead and winning the first two frames the following day to seal a stunning victory.
Michael Wasley v Ding Junhui (2014)
Wasley was making his Crucible debut against an in-form Ding, who came into the event on the back of winning five ranking titles during the season. Ding looked in command when he led 6-3, but Wasley recovered to trail 9-8 before the players were forced to come back for a rare third session after overrunning their allocated time slot. World number 73 Wasley produced a break of 103 to force a decider which he clinched on the final pink after midnight.
David Gray v Ronnie O'Sullivan (2000)
O'Sullivan had reached the semi-finals in 1999 and won the first of his five world titles in 2001, but in between suffered a shock defeat to Gray, who went on to lose 13-1 to Dominic Dale in the second round. O'Sullivan led 5-1 and 9-7 but could not scramble over the line and Gray held his nerve to secure a famous win.
Rory McLeod v Judd Trump (2017)
Trump was among the favourites for the title in 2017 and faced 1,000-1 outsider McLeod in the opening round, but could only manage a top break of 65 in a low-scoring contest. McLeod's highest break was only 77 but he played gritty match snooker to overcome an early deficit to win 10-8.
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