Ronnie O'Sullivan, who has won all four of the World Championship finals he has contested, sped through to a fifth today as he brushed aside the challenge of Judd Trump.

Armed with a 14-10 lead heading into the fourth session of their semi-final, the defending champion punished Trump errors to move a frame away from victory, and a flicker of a recovery from the young pretender was extinguished as O'Sullivan came through a 17-11 winner.

After almost a year out of snooker, the feat of reaching another Crucible showpiece match ranks among O'Sullivan's finest achievements. He has already this week claimed this will be his last appearance at the Crucible.

O'Sullivan said: "I'm quite surprised really to be talking about another World Championship final.

"It was tough because I don't think we played anywhere near our best."

Trump was 50-39 ahead in the opening frame today but missed a red to a corner pocket and O'Sullivan rifled in a 41 break.

O'Sullivan pinched the next after winning a tactical battle and finishing off with a crowd-pleasing 33.

Trump crashed in a 77 break to give himself the slightest hope, but the reprieve was all too brief as O'Sullivan creamed off breaks of 31 and 33 in the next frame to clinch a showdown with Barry Hawkins in the two-day final, beginning tomorrow. 

O'Sullivan said of the head-to-head with Trump: "There was a lot of tension out there during the sessions. We practise in the same environment, we used to be managed by the same manager, so that creates a kind of derby match feel.

"Everyone was really geared up for it because it was the newcomer against someone who's been around a long time and wears his heart on his sleeve.

"I might say some things that frustrate people at times but my fans they always get behind me because they know I try my hardest every time I go out there."

Last night O'Sullivan was ticked off by referee Michaela Tabb for what the Scot perceived as a rude gesture during last night's third session of the match.

O'Sullivan lost concentration and looked bored as the 23rd frame of the match became scrappy.

When he played a shot he found particularly poor he motioned with his cue between his legs and Tabb stepped in to issue a brief reprimand.

It was not a formal warning from Tabb and O'Sullivan denied trying to cause offence, apparently arguing his cue was sticky and he was trying to solve the problem.

Today he stuck to his guns when asked whether Tabb had misunderstood his actions.

He said: "I think so. My hands are sticky, you get sticky hands through sweating, my (cue) butt was sweating maybe."

Trump felt his performance had lacked sparkle.

He said: "I feel disappointment really because I did have chances and in the first two sessions I really struggled.

"As soon as he got in front he was so difficult to peg back. My scoring wasn't good enough at this level and it was the worst I've played in this tournament.

"He scored a lot heavier than I did. You've got to score while you're in. I probably got in first more than he did which showed how good my safety was.

"But over the tournament he has missed less easy balls than the rest of us."

Trump also urged O'Sullivan to reconsider his plans to walk away from snooker.

"Hopefully next year he plays in it again so I can beat him," Trump added.

"I want to win the World Championship with him in it and I want to beat him on the way."