Mark Selby's 6-5 win over Mark Allen yesterday to reach the semi-finals of the Masters extended his unbeaten record at Wembley Arena to six matches.

Selby laboured for four hours and 32 minutes to a 6-5 win over Ricky Walden this week and admitted he felt inhibited by his status as defending champion. But there were no such inhibitions yesterday in a contest of the highest quality.

The 22-year-old Allen, 16th in the rankings, is Northern Ireland's best prospect for major titles since Alex Higgins and Dennis Taylor. Aggressive and fluent, he turned a 2-0 deficit into a 4-2 lead but Selby levelled with breaks of 92 and 120, and there was an exchange of centuries as the score reached 5-5.

Selby was lucky at 27-0 in the decider to pot a red out of a snooker and then not to leave a clear chance when he missed an easy ball at 33-0 but, when Allen's attempt to pot a red from distance failed, Selby made another 33 to progress.

John Higgins, winner of October's Grand Prix in Glasgow, beat China's No1, Ding Junhui, 6-4 and will meet Selby for a place in the final.