By Julian Shea
BBC Sport at The Crucible
Ian McCulloch earned a semi-final with Matthew Stevens after a fine display of potting to beat Alan McManus 13-8.
McCulloch's afternoon dominance proved decisive
The Lancastrian dominated the truncated afternoon session, taking his time but winning all six frames to go 9-5 up.
Two of the afternoon frames were put back until the final session where McManus won three of the opening four, and he looked to be finding his rhythm.
But unanswered breaks of 75 and 73 put McCulloch within reach of a win, sealed when he took the final frame 70-18.
McCulloch and Stevens start their semi-final at 1900 BST, with Peter Ebdon taking on 22-year-old qualifier Shaun Murphy in the other semi at 1400 BST.
McCulloch said he was optimistic of beating Stevens despite previously losing to him twice.
"You've got to treat the semi-final like any other match," said McCulloch.
"A lot of people have played at The Crucible but a lot of people have not got down to the one-table situation.
"I've played Matthew Stevens twice and I think and he has buried me twice. But at this level, past records stand for nothing though."
Alan McManus was left deflated after losing to qualifier McCulloch.
"At 9-5 down it was a big lead to come back from," said the Scot.
"I missed a few chances as well and you can't afford to miss those. I was sitting in my chair for long periods. It was a difficult to get going.
I don't take positives from the game. I won a couple of games, but I really wanted to go further than that."
A McMANUS (Sco) 8-13 I McCULLOCH (Eng)
31-101 (73) 0-125 (124) 0-119 (74) 64-24 67-13 (55) 72-29 (71) 66-42 66-59 43-67 0-98 (52) 0-76 (76) 41-50 0-64 9-61 75-1 (63) 62-24 44-73 91-0 (79) 0-75 (75) 0-74 (73) 18-70