Mark Allen crashed out of the Northern Ireland Open at the last-32 stage as the world No.3 was upset by Oliver Lines in a dramatic seven-frame battle.

Allen entered the Waterfront Hall tournament bidding to improve on a disappointing last-64 exit 12 months ago after winning the NI Open two years in a row.

Instead, Leeds man Lines – ranked 80 places below his opponent – claimed a major scalp and bolstered a rising reputation having reached the British Open Semi-Finals in September.

The 29-year-old won the last two frames after Allen nudged in front 3-2. The Antrim star was unable to win the one frame he needed to secure victory.

Home favourite Allen, the Northern Ireland Open champion in both 2021 and 2022, hit back in the second and fourth frames of a nip-and-tuck battle, with world No.83 Lines winning both the first and third frames to edge ahead only to be pegged back by the Antrim cueman to leave the score level at two frames apiece heading into the crucial fifth frame.

Both had advanced into this last-32 showdown on the back of comfortable last-64 wins, with a 4-1 victory for Lines over China’s Wu Yize on Tuesday teeing up his meeting with Allen who swept aside Liu Hongyu 4-0 on Monday, but this game was tension-filled and the fifth frame alone lasted over 40 minutes before Allen moved in front for the first time.

However, Lines was far from done, forcing a decider in the best-of-seven showdown by winning frame six and prolonging a battle where there had been little to separate either man.

It was crunch time for Allen as he looked to keep his pursuit of glory alive at Waterfront Hall, but Lines hit the front early in the final frame and built up a lead he would not relinquish to with 4-3 and set up a last-16 date with either Australia’s Neil Robertson or Hong Kong’s Wang Yuchen.