By Dan Warren
BBC Sport at The Crucible
Matthew Stevens survived a brave Joe Perry fightback to book his fourth Crucible semi-final appearance in five years with a 13-10 win.
Stevens had to weather a Perry fightback
Resuming 11-5 up, Stevens contrived to allow Perry back into the match, losing the first three frames on the trot.
The Welshman showed none of the class he displayed previously in the match, and despite edging a scrappy 20th, Perry won the next to make it 12-9.
Perry moved to 12-10 with an 80 break, before Stevens finally sealed victory.
Stevens admitted he nearly lost his nerve as Perry came back at him.
"It's difficult when you have a big lead like that and then someone fights back, because it really puts the pressure on you," he said.
"I actually feel relaxed now I have the match out of the way. I'm into the semis and I know what to expect."
Perry admitted he thought he could pull off one of the great Crucible comebacks.
"I gave myself a hell of a lot to do in the first two sessions, but I felt 'I can win this'," he said.
"I wasn't surprised to see Matthew struggle. It's so hard to win matches here even if you're the favourite.
"I lost the match at the start. I was still mentally tired after beating Mark Williams in the second round."
M Stevens (Wal) 13-10 Joe Perry (Eng)
72-39 1-108 45-78 77-8 128-0
73-61 10-65 69-37 72-44 17-63 134-0 93-4 68-2 68-1 66-32 55-80
31-60 28-67 24-62 78-41 54-80 29-85 63-26