Judd Trump's 13-9 defeat to Kyren Wilson makes him the 18th victim of the so-called 'Crucible Curse' of first-time winners who have failed to defend their title.
Here the PA news agency looks back at five more champions who have been brought crashing back down to earth.
Steve Davis (1982)
Davis won his first world title in 1981 defeating Doug Mountjoy and would go on to claim five more crowns. But in his first defence he was stunned by Bolton qualifier Tony Knowles, who headed to a nightclub after fashioning an 8-1 overnight lead and returned the next morning to win the two frames required to complete the job.
Stephen Hendry (1991)
Hendry beat Jimmy White to win his first title in 1990 and was expected to dominate the scene for years to come. But after easing through the first two rounds he fell 13-11 to ninth seed Steve James in the quarter-finals. While James's career would subsequently fall apart, Hendry returned the following year to win the first of five world titles in a row.
Mark Williams (2001)
Williams was bundled out of the tournament by 16th seed Joe Swail in the second round of his title defence. Williams looked set to ease into the last eight when he led Swail 11-7 and 12-11, but the Northern Irishman produced a thrilling comeback to ensure Williams would join his illustrious predecessors in failing to retain his title.
Ronnie O'Sullivan (2002)
Defending champion O'Sullivan whipped up a grudge match against Hendry on the eve of their semi-final clash in 2002, claiming he wanted to send the Scot back to his "sad little life". Hendry was unperturbed and dispatched the 'Rocket' 17-13 en route to suffering a last-frame final defeat to Peter Ebdon.
Mark Selby (2015)
Selby joined the growing list of defeated first-time champions when he suffered a shock 13-9 second-round defeat to Crucible debutant Anthony McGill. Selby shrugged off the loss and returned the following year to win the first of two consecutive crowns – and is still in the running to claim a career fourth in this year's tournament.
