Ronnie O'Sullivan produced some of the magic that enabled him to win four world titles as the defending champion took a 9-7 lead over Ali Carter in their World Championship second-round clash on Sunday.
O'Sullivan held a 5-3 lead from the first session at the Crucible, but he was under pressure as Carter hit back to level at 7-7.
That prompted O'Sullivan, who has spent much of the last 12 months away from snooker, to demonstrate why he remains the world's best player.
O'Sullivan, who has beaten Carter in two Crucible finals, regained the lead with a fluent 73 break.
And when Carter missed a long red in the final frame it gave the 37-year-old O'Sullivan another chance.
He never looked like missing on his way to restoring the two-frame cushion which puts him within four frames of victory and a place in the quarter-finals heading into Monday's final session.
Before Carter produced his own wayward long red, it was O'Sullivan's potting that was looking shaky from anything beyond medium range.
He fluffed two in the second frame of the afternoon and Carter punished him. When O'Sullivan missed another red early in the next, Carter eased to an 87 break.
At a tournament where burnout has been cited as a factor in the early demise of so many big names, O'Sullivan was supposed to be the freshest man in the field, having taken most of the year off since securing his fourth title at the Crucible last May.
He looked that way when he fired in 105, his second century of the match after Saturday's 125, to lead 7-5.
But O'Sullivan missing a frame-ball black to halt a break on 61 in the next frame put Carter in with a chance to steal, and he held his nerve to make 63 and give O'Sullivan food for thought.
It was soon 7-7, with O'Sullivan rattling another black in the jaws early in the frame.
That was it for Carter, who could only watch as O'Sullivan produced some scintillating snooker when he needed it.
In each of the last two frames, he made a cross-table double of the highest quality to stay at the table and pile on the points that means he remains on course to stay unbeaten against Carter at major tournaments. This is their 13th meeting and it looked like it was going the same way as the previous 12.
Meanwhile, China's Ding Junhui had breaks of 59, 98, 74, 81 and a closing 103 as he came from 6-2 behind against Mark King to lead 9-7 going into Monday's final session.