Ken Doherty beat Matthew Stevens 9-7 in a marathon encounter in the UK Championship quarter-finals.
There was little to choose between the duo throughout a scrappy night session.
Despite resuming with a run of 117, Stevens could not add any further half-century contributions.
And Doherty ground out a hard-fought success, a break of 69 securing his progression.
"It was always going to be a tough battle," said Doherty.
"Matthew started like a train, going 6-4 up, and I just had to keep fighting.
"I got back to 6-6 and then thought I'd blown it when I lost a frame I should have won and the last few frames were very tense. I think we were both feeling the pressure."
The world number four will face Stephen Lee in the semi-finals.