Anthony Hamilton won the first five frames of Saturday's second session to defeat Ian McCulloch 13-8 and reach the World Championship quarter-finals.
The players were locked at 8-8 after a scrappy and mistake-ridden opening session with Hamilton recording breaks of 60, 61 and 63.
Hamilton had a storming start to the second session and breaks of 111 and 107 put him on the brink of victory. And he sealed a last eight place for first time since 2004 with a run of 91.
Northern Ireland youngster Mark Allen won three consecutive frames at the end of his second session against two-time runner-up Matthew Stevens to trail 9-7.
The Welshman looked to be on course for a quarter-final meeting with Shaun Murphy when he led 9-4 but the 21-year-old, who knocked out Ken Doherty on his Crucible debut, hit back to give himself every chance for tonight's conclusion.
