Trump needs just two more frames to seal a place in the last eight after winning the session 6-2 at the Crucible Theatre in Sheffield.

Gilbert looked set to draw level with Trump at 5-5 before an act of sportsmanship handed the initiative in the frame to his opponent.

He asked for the balls to be replaced with the white still moving after Trump had failed to get out of a snooker.

The white ended up in the pocket, which would have given Gilbert an advantage, but he said his original call should stand.

It proved to be a decisive moment in the match as Trump took control from that point on.

Three-time champion Mark Selby of England held off a fightback from Northern Ireland's Mark Allen to take a 9-6 lead heading into tomorrow's decisive session.

Selby led 6-2 before Allen slowly chipped away at his advantage, with neither player able to exert any real influence over proceedings in a scrappy period of play.

England's Shaun Murphy, bidding for his first world title since 2005, is 10-6 in front in his encounter with China's Masters champion Yan Bingtao after they split their session today by winning four frames apiece.

Murphy's compatriot Stuart Bingham, the 2015 champion, leads Welshman Jamie Jones 10-6 after a composed performance in the evening session.

The tournament is due to continue tomorrow.