Mark Williams took it upon himself to do the job of the referee in his first-round match at the World Snooker Championship. The three-time champion was in the opening frame of his match with Yize Wu when the Chinese player fouled by potting the pink.

However, official Olivier Marteel did not initially call the incident. Williams then took it upon himself to rush around the table and pick the pink out of pocket and placed it back on the spot. Marteel followed him, smiling, before trying to explain the delay.

As Williams plucked the ball out, the crowd laughed before the Belgian said: "Yeah I was talking, I was talking to someone in the crowd. No it's ok (as Williams picked ball up)."

He then replaced the ball himself, before finally shouting: "Foul, Mark Williams, six." The TNT Sport commentators also joined in with the humour, with one saying: "He's made an excuse for not calling it, that he was talking to someone.

"But to be honest, he should have remembered it anyway. He didn't like it that Mark took that pink out, he put it back on the spot himself, he was having none of that."

The co-commentator referenced the personality of Williams, adding: "He's always had a wicked sense of humour, Mark. He loves a wind-up."

The incident certainly didn't seem to affect Williams's focus. He went on to make a break of 57 to take the opening frame, and then also came through a scrappier affair to lead 2-0.

A rattled Wu continued to make errors in the third, and Williams extended his lead to 3-0. However, Yu did settle before the mid-session interval, making a break of 120 to take the fourth frame to reduce the deficit.