China's Liang Wenbo lacked some luck to outlast the defending champion John Higgins who overcame first night nerves to reach the last 16 of the World Championship with a 10-9 victory on Saturday.
Four-time winner Higgins, who led 5-4 after the first session, was in serious jeopardy of an early exit when he lost four straight frames to trail 8-6.
"I thought he was closing me out," said the exhausted winner after the six hours and 13 minutes clash.
"I don't know how I've won it really, I probably didn't deserve to win it because I didn't play anywhere near well enough to merit winning that game. I just can't believe I've won."
However, inspired by a 133 total clearance in frame 15, the Wizard of Wishaw fought his way back to level at 8-8. He re-took the lead with a break of 58 then world No 38 Liang responded with a 75 to force the decider.
Liang had the first chance but fouled in potting a red, admitting it immediately to the referee. Higgins made a break of 40 then missed a red to a centre pocket, and Liang overtook the lead with 52 before running out of position with two reds left.
Higgins then never looked back to clinch the decider in 77-52, avoiding to become the second consecutive defending champion to fall on the first day after Neil Robertson last year.
He is now likely to face Stephen Hendry in the last six after the seven-time world champion led Stuart Bingham 8-1 in the first session, highlighted by a 147 maximum break, which was his 11th in career.
While Liang, who lost all the previous three meets against the 36-year-old Scottish, had to leave snooker's biggest stage after the hard-fought qualification to the Championship.
"It's really a pity that I ended in this way. But you cannot think about it too much. Next year, I will try again," said the 25-year-old.
Chinese players made a record number of five in advancing to the the 1.1-million-pound tournament this year.
The Crucible Theater debutant Cao Yupeng, who turned professional last year, also stunned the more experienced Mark Allen with an early 3-0 lead.
The Haikou World Open champion fought back to close the gap, trailing 5-4 after the first session. The opponents will fight for another last-16 berth on Sunday.