John Virgo was left seething after the opening frame of the night between Mark Williams and Hossein Vafaei required a re-rack. The pair started the evening session locked at 4-4, with the Iranian taking an early 20-10 lead.

Earlier in the frame, Williams scattered the reds, leaving some in unfavourable potting positions. A dour period of safety play followed, with the stalemate continuing for almost an hour. Eventually, both players then agreed to restart the frame, prompting groans from some spectators.

Virgo was left distinctly unimpressed. It was the fifth re-rack of the match, and the 79-year-old argued that fans were being denied seeing proper action.

"I know it's the World Championship and every frame is important but that's a little farcical," he said. "The players were reintroduced at 7:08pm, and now it's nearly 8pm and we still haven't seen a frame of snooker. That's the bottom line."

It was three-time world champion Williams who eventually took a 5-4 lead. When play did get back underway, there was no repeat of the dour first hour as he racked up a superb break of 122.

It could have been better had he not potted the cue ball on the pink as he eyed a big clearance, but his effort was met with healthy applause from the patient crowd.

By the time Williams produced his ton break, Virgo had calmed down, saying: "Mark Williams will take great stock out of that opening frame with a good century to boot."

The match got underway at the same time that Mark Allen and Chris Wakelin resumed their battle. With Allen trailing 12-4 from this morning, the Northern Irishman had already won two frames, and was deep into the third, when Williams got on the board.