Stephen Maguire does enough to secure place in semi-final

The match was scrappy throughout, with Day frequently wasting chances to wrap up frames and Maguire capitalising. Though the score looked one-sided, the Welshman was within one pot of reaching the mid- session interval on level terms.

Trailing 2-1, he moved into a 26-point lead in frame four with just the colours remaining – only to jaw the frame-ball yellow and watch his opponent clear the colours and pinch the frame for a 3-1 lead.

The same pattern repeated itself after the break, as Day ground to a halt on a break of 44 in the sixth frame and a break of 62 to the pink allowed Maguire to move within one frame of victory. And a run of 61 sealed a similar seventh frame, and victory, for Maguire.

But the Scot said: "The first session was getting to the point of being embarrassing – maybe if one guy knocked in a hundred it might have spurred the other one on, but it was awful. It shouldn't be like that, (if one player misses) the other guy should just pounce.

"I've won two matches without playing well – I could have been out in the first round and I could have been out there. The first priority is to get through the match, you can always improve in the next match."

Meanwhile, Ronnie O'Sullivan was again thoroughly underwhelmed with his performance after beating Peter Ebdon 6-3 late on Thursday night.

O'Sullivan delivered a scathing appraisal of his game after fighting back from 3-0 down to beat Neil Robertson in the last round, saying a lot of the time he was playing "sub-standard shots".

There appeared little to be unhappy with early on as the Essex potter raced into a 4-0 lead in just over an hour, but O'Sullivan was especially irked by how he finished the contest.

"Peter could have won the game quite easily," he said. "I would rather be 3-0 down and hit a bit of momentum than be 3-0 up and feel like I'm stalling when I come to the table. Most of the time I'm missing a lot of shots and it was difficult to find confidence out there. The long game I've got at the moment is just laughable."

O'Sullivan got off to a flying start as breaks of 92, 53 and 74 in the opening three frames helped him seize control of the match.

Ebdon stopped the rot as a fluked final red helped him take the fifth frame and the 2002 world champion reduced the deficit to two by edging a tight sixth despite a 54 break from his opponent.

O'Sullivan moved to within one frame of victory, only to be pegged back again by the 2002 world champion before a 106 got him over the line.