O'Sullivan closing in on final
Ronnie O'Sullivan faced a Crucible ticking-off but regained his focus to move within sight of a place in the World Championship final.
The defending champion lost all his concentration and looked bored as the penultimate frame of the night against Judd Trump became scrappy.
When he missed a ball he expected to rifle into the pocket he ran his hand up the shaft of his cue between his legs and referee Michaela Tabb stepped in to issue a brief reprimand, with O'Sullivan seeming to say "I wanna go home".
He denied trying to cause offence, arguing his cue was sticky and he was trying to solve the problem. He lost the frame but took the last of the night to go 14-10 in front, three away from his fifth World Championship final.
Having begun the day level at 4-4 in the match, to come through two sessions with a four-frame cushion was a fine achievement for O'Sullivan.
On Friday night he had breaks of 51, 62 and a closing 89 to punish Trump for a series of misses that suggested he was feeling the pressure of the semi-final occasion.
O'Sullivan swept through the opening frame of the night and made Trump pay for a missed blue towards the end of the next, clearing up the final three colours.
Trump needed to stamp some authority on the session and a 117 break, the first century of the match, went some way towards doing that.
Trump also had a chance in the next frame but touched the yellow with his arm when taking on a red with the rest and called the foul on himself. O'Sullivan potted the red and made 62 as he restored the four-frame cushion at 12-8.
When Trump took two of the next three to narrow the gap, he had the momentum going into the final frame, yet O'Sullivan disrupted that to end the evening on a positive note.
The quality of O'Sullivan's tussle with Trump was not being replicated by last-four debutants Barry Hawkins and Ricky Walden in the second semi-final, with the pair limping through their afternoon session, Walden going from 6-2 to 9-7 in front despite his opponent remaining without a half-century break in the match.
Chester-based Walden fired in 106, his third century of the match, to lead 8-5, but then saw Kent cueman Hawkins claw his way back.
Hawkins had struggled badly yesterday, managing a top break of just 36, and his break-building trouble persisted as the match progressed.
Eventually he managed to improve on it, allowing himself a small fist pump during a break of 47.