MARK Selby capitalised on a stroke of cruel luck for opponent Mark Williams to reach the Dafabet Masters quarter-finals at Alexandra Palace.

World number one Selby stayed on course to add the Masters to the World Championship and UK Championship trophies already in his possession, edging out Williams 6-5 in London.

It seemed Williams was on course to cause a major upset when he began to build a break in the deciding 11th frame, only for an unlucky kick on the blue to send the ball fractionally off its intended course.

The bad contact – not the fault of Williams – halted the frustrated Welshman in his tracks, and Selby produced an 89 break to take frame and match.

Selby sympathised with the two-time former Masters champion, as he kept his own bid for a fourth triumph alive.

“It’s one of them where if I’m playing it I’ll probably punch it in to take the kick out of the equation,” Selby told BBC Two.

“But that’s the way Mark plays, he always rolls everything and he’s won so much in the game by doing that, so why should he change his game?

“It’s just very unfortunate.”

Steve Davis, the three-time former Masters winner, said: “There’s no way it won’t hurt.”

Williams had gamely taken Selby all the way to the decider, fighting back from a 3-1 interval deficit.

Selby had early breaks of 139, 62 and 109 in successive frames, but in the end was relieved to get over the line.

His quest to be the holder of each of snooker’s big three Triple Crown titles remains on target, and Selby had that on his mind as he headed to London from his Leicestershire base.

“That was on my mind coming here,” Selby said.

“It’s such a tough tournament to win anyway.”