Northern Ireland Open: Holder Mark Allen sets up semi-final with Neil Robertson

Defending champion Mark Allen edged out Mark Williams 5-4 to progress to a semi-final meeting with Neil Robertson at the Northern Ireland Open.

Allen trailed 2-0 but breaks of 77 and 74 brought him level by the mid-session interval before he moved 4-2 up.

Williams fought back to 4-4 before Allen clinched a tense decider.

Earlier, Australian Robertson beat Mark Selby 5-2 while Scotland's Anthony McGill and and China's Zhou Yuelong progressed to the other semi-final.

McGill trailed another Chinese player, Lyu Haotian, 2-0 but breaks of 56, 95, 85 and 112 in the penultimate frame helped the Scot clinch a 5-3 victory.

Earlier, Zhou took the final three frames of his contest with England's David Gilbert to snatch a 5-4 win.

Breaks of 71 and 84 put Gilbert on the brink of victory at 4-2 up but Zhou responded with runs of 63, 54 and 130 in the concluding three frames as the Englishman missed two crucial blacks off the spot.

Robertson and Selby produced a high-quality contest with the Australian winning frame one thanks to a break of 73 only for the Leicester cueman to move 2-1 up helped by a run of 95.

The 2010 world champion responded with a break of 97 to level by the mid-session interval and a further effort of 84 then moved him ahead.

Selby looked set to level in typically gutsy fashion as he forced a series of fouls from Robertson after the Australian had started frame six with a break of 63.

However, a crucial missed yellow gave Robertson a reprieve as he moved 4-2 up, and breaks of 73 and 53 sealed his victory in frame seven.