Mark Allen and Wu Yize play the longest frame at the Crucible ever in World Championship semi-final

Wu would win it, eventually, after requests for a re-rack, protestations from Allen, and a number of audience members desperately pleading to go to the toilet.

In the end, with the score 7-7, the players were hauled off not long before 7pm with only six of the scheduled eight frames played, that after over four hours of snooker which shifted from the sublime to the ridiculous.

The sublime came from Allen who began the session trailing 6-2 but surely ended it the happier of the two men, his comeback kickstarted by winning a couple of scrappy frames to start, the second on the final black.

Moments later the Northern Irishman compiled a flawless total clearance of 145, the highest break of the tournament so far, and after controlling the following frame, he added another century to make it five on the spin.

What proved to be the final frame of the afternoon was described by Stephen Hendry on the BBC as the 'dark side of snooker', the black hanging over the bottom corner pocket and converged by a pack of reds for what seemed like an age, until the deadlock was broken by Allen when he opted to purposely foul the black into the pocket.

Nevertheless, Wu did well to hang tough, battling his way into the ascendancy and then escaping from a terrific snooker laid by Allen on the final pink to ensure he had something to show for his afternoon's toil.

The match resumes at 10am on Saturday.