Ronnie O'Sullivan moved 15-10 ahead of Ali Carter after the third session of the World Championship final on Monday, having led 10-7 overnight.
Carter staged a fightback from 14-7 behind to narrow the gap to four frames, firing his first century of the match in the process, before O'Sullivan ploughed in breaks of 64 and 55 to go three away from the title.
The 36-year-old Chigwell cueman had been silky smooth at the start of the day's play, caressing a long red in before cruising to his third century of the match, a 101, and taking all four frames before the mid-session interval.
On Sunday O'Sullivan fired in breaks of 117 and 141, the latter the highest break ever achieved in a Crucible final.
He and Carter were due to return at 7.30pm for a maximum of 10 frames.
Also on Monday, O'Sullivan's sports psychiatrist insisted the long-term happiness of the snooker showman was more important than guiding him to another world title.
Dr Steve Peters began work with O'Sullivan 13 months ago and persuaded the three-time world champion to play at the Crucible last year.
As O'Sullivan pursued a fourth world title on Monday, Dr Peters spoke at length for the first time about his role in helping his star patient handle the pressure and strains of professional snooker.
O'Sullivan was ready to retire before teaming up with the Sheffield-based doctor.
"It was this time last year I met him when he was going to the World Championship. He's been an absolutely amazing pupil," Dr Peters told BBC2.
"He's done everything I've asked of him. Credit to him because not everyone can do that.
"It would be brilliant if he won the title, but I think the ultimate is that he goes away happy. That's a bigger challenge than winning this [the world title].
"I think he'll do well, I think he's in a very good place at the moment."
Dr Peters added to BBC Radio Five Live: "Watching Ronnie in action has been absolutely brilliant.
"I'm a doctor coming from hospital medicine, so as far as sports psychology is concerned, I'm completely fraudulent.
"I've just made it up as I go along and said, 'What can I take from my clinical knowledge and experience of the human brain and mind?', and 'How I can I apply it to this sport?'.
"With Ronnie, it's quite straightforward. You explain to him what's going on in inside his head and what they're allowed to use as an apparatus for thinking and feeling, and for emotion.
"They learn which parts of the brain actually work and how they can fit them to the paths they want.
"It's more about education and understanding, that way their skill-base builds up.
"Me and Ronnie have worked on a skills-base for 12 months now, and he's a fantastic pupil. He knows exactly what he wants and he doesn't want."
Dr Peters, who achieved huge success working with Britain's 2008 Olympic cyclists, explained his role in bringing the best out of all his patients.
He said: "Some people come in who are just as functional as anyone but they are not happy and sabotaging their own success. That is pretty universal in humans, and the area I specialise in.
"My take on this is that we as doctors are looking at the machine inside the head. It is like opening the bonnet of the car at the engine.
"If we understand it, if it does start to break down or falter, we can repair it ourselves. I try and repair as I can, and then teach the person, 'This is what's going on, you get up and do it'.
Although O'Sullivan has warned he could retire on Monday night, working with Dr Peters has given his career a major lift, and changed his life outlook.
Dr Peters added: "Just as he would come to a snooker table and practice his skills, I give him skills to move the blood supply around in his brain and get to a place he wants to be, and behave in the way he wants.
"He's not perfect, but in a much better place than he was 12 months ago. Credit to him, I can only teach him the skill, I can't get him to do it."