Defending champion Neil Robertson beat Mark Allen 6-5 in a gripping Masters quarter-final at Alexandra Palace. In the semi-final, Robertson will face Shaun Murphy who beat John Higgins 6-5 after being 4-1 down.

Robertson and Allen shared the first four frames, as Allen knocked in a 138 clearance, but the Aussie then went 4-3 ahead.

The Northern Irishman struck 68 to level at 4-4 and Robertson's 101 put him one away. Allen forced a decider and he laid a snooker, but his opponent escaped, making a century for the win.

Murphy now has the chance to become the eighth man to win the "triple crown" of World, UK and Masters Championships, but for Higgins it was a disappointing defeat having held a three-frame lead.

Murphy - the world number four - made a confident start, taking the opener with a knock of 85, although Higgins took the next three frames.

A break of 69 in the fifth allowed the Scot to extend his advantage, but Sale's Murphy was finally able to win another frame at one visit with a 70.

The following frame was a tense one with both players missing chances, and it was Murphy who took it on the pink to go 4-3 behind, as well as taking the next to level.

Higgins, number three in the world, clinched the ninth to go one away from victory. He had the opportunity to win the match but missed a red and Murphy took it to a decider, one which he won with a composed 66 to advance.