Mark Allen overcame tournament favourite Neil Robertson 6-4 to seal a semi-final place at the Ladbrokes Mobile Masters.
The match was a curious mixture of classy break-building and scrappy spells, Allen making five half-centuries to his opponent's four but the pair still requiring over three hours to complete the 10 frames.
“I think it was my safety that got me through today,” said Allen. “I've taken a bit of time, and started watching people who have been doing well.”
Robertson was gracious in defeat, backing Allen to go on and win the Masters.
The Australian said: “I can't really fault my performance today, and say I played badly. Mark played really well today, and in my opinion he is now the favourite to win the tournament.”
The Antrim potter made a break of 63 and then prevailed in a high-quality safety battle to win the opening frame, and also stole the second from 42-0 down with a run of 69.
A wonderful break of 69 to the pink got the Australian on the board in an initially scruffy third frame, and a 56 in the fourth helped him level matters at the mid-session interval.
Robertson went 3-2 ahead with breaks of 47 and 50 in the first frame back before the sixth became bogged down in containing safety play.
In missing a long red, Allen left two reds over pockets and was fortunate to cover both. The resultant difficulty of subsequent safeties saw around half the reds end up in the bottom half of the table before Robertson inexplicably left an easy pot with a dreadful safety.
Allen could manage only that solitary red on that occasion, but he put 46 on the board from his next opportunity to level at 3-3.
The next followed a similar pattern as the match went through a lull, but a thumping long red set Robertson on his way in a frame-winning break of 71.
Allen made a 57 in the next and snookered the Australian, who also needed snookers himself. After failing to hit the final red, he conceded and the scores were level once again.
A composed 75 took Allen within one frame of the last four and he took a 69-point lead in frame 10 but missed the red that would have clinched the match.
Two over-ambitious shots from Robertson left relatively easy chances, which were wasted, but Allen finally got over the line with red and pink.