Ronnie O'Sullivan put a lethargic start behind him to move two frames away from a place in the Betfred.com World Championship final.
The 36-year-old started so slowly it seemed Matthew Stevens, 11-5 behind heading into the session, would significantly close the gap ahead of Saturday night's concluding session.
At one stage Stevens got back to 12-9, having taken four of the opening five frames, but the final three went O'Sullivan's way and at 15-9 behind it was looking to be a case of completing the formalities when they returned.
Welshman Stevens was initially far the perkier player, producing his best snooker of the match, while O'Sullivan was in slumber mode.
The Chigwell cueman's best form in this tournament has come in afternoon sessions, in which he has strung together six-frame winning bursts against Mark Williams, Neil Robertson and Stevens, who felt the force of O'Sullivan at his best on Friday.
The 10am start may have been a factor in his unsteady form, with Stevens taking the first two frames with a high break of just 44.
O'Sullivan came to life with runs of 50 and 68, before Stevens captured frames either side of the mid-session interval, the first thanks to a 66 break.
Stevens' third frame of the morning banished the prospect of a finish in the match with a session to spare, and his fourth hinted he might make a real contest of the match.
But then O'Sullivan swept to an 81 break in six minutes, and despite failing to scale those heights in the next two frames, still managed to pinch them.
Stevens, though, should have had the second of those frame, the last of the session.
He led 52-37, having just potted a glorious long red with the fierce, deep screw that Judd Trump made his trademark last year.
Brown to the middle pocket was by comparison an easy shot, yet Stevens missed his target by a clear inch.
The likelihood of 14-10, giving Stevens a fighting chance, was taken away as O'Sullivan raced to 39, taking the frame and keeping alive the possibility of the red-hot title favourite making a swift getaway tonight.
