Maguire defeats Williams in Welsh Open

Williams won his first two matches 4-0 and was set for a 3-1 interval lead but Maguire made it 2-2 before sealing his fourth win in five versus the Welshman.

In the semi-finals, Maguire will face Mark Selby, who beat Graeme Dott 5-3.

Defending champion John Higgins ended Welsh hopes by beating Matthew Stevens, with a 132 in a 5-3 win, and will play Ali Carter who ousted Ding Junhui 5-2.

Maguire eliminated Williams at the same stage of this tournament last year and a break of 45 gave him the early advantage.

Williams hit back with a 54 and after Maguire rallied to make it 2-2, the left-hander delighted the home fans with a neat plant that led to a break of 63 and a 3-2 lead.

A superb 105 clearance from Maguire levelled up the match again and the Scot moved ahead courtesy of a 68 after Williams failed to capitalise on a golden opportunity and missed a straightforward red.

One frame from defeat, Williams attempted an ambitious plant into the centre pocket and though the resulting Maguire break was only 26 and later missed a routine brown into the bottom corner, he soon left his opponent needing snookers.

Unfortunately for Williams and the home support, it was Maguire who played the perfect snooker behind the green and when Williams crashed into the black he conceded defeat.

"I've just beaten the man in form," said Maguire, the world number eight. "I've underachieved a lot in the last couple of years. I look at the other players winning tournaments at the moment and if it was me playing them, I think that I could beat them. It's just getting to a point where I am playing well enough to do that."

Selby took a commanding 3-0 lead in his match against former world champion Dott, which was littered with errors from both players.

The Scotsman reduced the deficit to 3-2 after runs of 62 and 47 but Selby restored a two-frame cushion after an 88 in frame six.

Dott won the next and led 21-0 in frame eight but Selby compiled breaks of 43 and 25 to go through.

"I think sometimes you can try too hard and it stops you from relaxing and playing well," Selby told worldsnooker.com. "But as long as I keep winning I don't mind how I play."

Dott was in despondent mood after the defeat and said: "I'd have to say that it's not possible for me to play any worse than that."

Stevens, whose defeat means he will not return to the coveted top 16 and has to qualify for the World Championships, began well against Higgins with a break of 77 in the opening frame.

World number one Higgins moved 3-1 ahead with his 132 break but Stevens responded with runs of 93 and 58 to level the match at 3-3.

Higgins went ahead again but Stevens had a fine chance to take the match to a deciding frame.

However, leading 53-30, he missed a long red and Higgins held his nerve with a composed clearance of 39 to the pink to progress to a semi-final against Carter, a repeat of last year's final.

"Matthew had a lot riding on this and maybe missed a couple of balls which you don't expect him to miss," Higgins said. "Luckily I held my nerve to clear up at the end."

Carter, who won his first ranking title at this event in 2009, reeled off breaks of 76 and 74 to beat a strangely out-of-sorts world number five Ding.