Gary Wilson finally shook off Mark Selby to win their Tour Championship encounter 10-8 and advance to round two.
Wilson had taken a 5-3 lead into Tuesday's second session and extended his advantage to 7-4, but when Selby won a tense 17th frame to claw his way back within one, a frustrated Wilson looked vulnerable.
Selby then worked his way into a lead in the following frame but missed a vital red to allow Wilson the chance to finally close the door, one he took impressively with his second century of the match.
Next for Wilson is a meeting with breakout performer Zhang Anda.
"I don't know how I won, to be honest. I'm just thankful Mark didn't play very well," said Wilson, who was vocally unimpressed with his own performance.
"Incorrect," he replied when ITV's Rob Walker suggested he'd been cueing well at times. "That's why I missed so many easy balls, played so many bad safeties.
"If I'd have been playing decent, I should've won that 10-3, 10-4.
"I'm sort of self-sabotaging, knowing I'm playing that bad. I couldn't even hit the ball properly.
"I don't know how I've won. I need to find something between now and Thursday. That's (playing poorly) not what I'm here for."
Ali Carter will face bitter rival Ronnie O’Sullivan in the quarter-finals after holding off a spirited fightback from Barry Hawkins.
Carter raced into a 7-1 lead after Hawkins had won the opening frame, but the left-hander won seven of the first nine frames in the evening session, including taking the 17th frame on a respotted black after needing two snookers.
However, Carter held his nerve to win the next and seal a 10-8 victory which sets up a showdown with O’Sullivan, 11 weeks after the pair were involved in a war of words following the Masters final won by O’Sullivan.
“I relish the challenge now because he’s the best player ever to pick up a cue,” Carter told ITV4. “To play him in another quarter-final, I’ve played him in a final this year, I’m in the right place.”
Mark Williams produced a superb clearance of 66 in the deciding frame to edge out Tom Ford 10-9 and set up a quarter-final with Judd Trump.
“I was dead on my feet for the last hour and three quarters, I was absolutely shattered,” said Williams, who has just returned from a trip to China.
“I thought it was all over. Where that clearance in the last frame came from I do not know. It was probably one of the best clearances I’ve done.”