At the 2020 World Snooker Championship, O'Sullivan made his 28th consecutive appearance at the Crucible, beating Stephen Hendry's previous record of 27. He started the tournament by beating Thepchaiya Un-Nooh 10–1 in the fastest match in Crucible history which lasted just 108 minutes. He then beat Ding Junhui and Mark Williams (after being 2-7 and 4-8 down) 13–10 each to reach his twelfth Crucible semifinal, where he faced Mark Selby. O'Sullivan won the first session 5–3, but lost 10 out of the next 14 frames to trail 9–13. O'Sullivan won the next four frames to level the match, but then fell behind 14–16 before making breaks of 138 and 71 to take the match to a deciding frame. O'Sullivan made a 64 break before missing a red to the green pocket. Selby scored 34 points before a safety battle on the last red took place. O'Sullivan eventually potted the last red and then cleared the table up to the blue to progress to the final. After the game, Selby accused O'Sullivan of being "disrespectful" after O'Sullivan had played several hit-and-hope shots while snookered. He responded by saying "if I was as good as Mark at escaping from snookers, I could maybe get it safe".