Ronnie O'Sullivan suffered one of the World Championship's great upsets as he went down 10-8 to amateur Crucible debutant James Cahill in the first round on Tuesday.
The five-time champion passed up numerous opportunities to recover after trailing 5-4 overnight and Cahill, the first amateur to play at the World Championship, showed incredible composure in the final frames.
O'Sullivan, 43, had crashed out in the second round in two of the past three years and this time did not even make it to that stage, with Cahill booking a meeting with Stephen Maguire.
The youngster recovered from a frame down three times on Monday and responded again when he was pegged back early the next day, with top-ranked star O'Sullivan levelling.
Cahill, 23, then raced 8-5 up - within two frames of an incredible victory - and looked to be on course to pull further clear until missing a straightforward red.
That allowed O'Sullivan in to reduce the arrears and he continued to prey on Cahill's errors, seemingly regaining his composure as he drew level again.
Another big chance looked to have gone begging for Cahill as he led by 54 points with 75 remaining in the 17th frame, but O'Sullivan's costly miss on the pink and subsequent failure to play safe saw the rookie nudge back in front.
O'Sullivan came out all guns blazing when granted an opening in the following frame, yet he sent down a red as he potted the blue.
Cahill was back in the driving seat and, under intense pressure, able to sensationally traverse his way around the table to seal victory.