China's Liang Wenbo claimed a place in the quarter-finals of the 888.com World Championship after an extraordinary last-frame thriller with Irishman Joe Swail.
Liang, who beat Ireland's 1997 champion Ken Doherty in the first round, held his nerve to win 13-12 and set up a last-eight clash with Ronnie O'Sullivan on his Crucible debut.
The 21-year-old led 12-8 at one stage and looked to have the match won when he led 12-10 and 59-44 with only pink and black remaining.
The left-hander punched the air after potting what he thought was the decisive blue but, after missing a tough pink into the middle pocket, Swail laid a good snooker, Liang missed, and Swail cleared up to reduce the deficit to 12-11.
Liang's celebrations were looking increasingly premature as Swail took the 24th frame to force a decider, a break of 66 enough to make it 12-12.
And there was still time for another twist in the decider as Liang led by 27 points with only 27 left on the table, only to again fail to get out of a snooker.
Liang was then desperately unlucky to knock the green in when attempting to pot the yellow, but Swail missed a simple brown and the Chinese youngster finally sealed a remarkable victory.