Ronnie O'Sullivan insists he can avoid a Crucible meltdown as he closes in on a fifth Betfair World Championship title.

O'Sullivan credits sports psychiatrist Dr Steve Peters as the key figure behind his wellbeing on and off the table, with the once-volatile 37-year-old former world number one now capable of keeping his feelings in check.

Where once O'Sullivan could lose focus in a flash, working with Peters has prepared him for the long-haul demands of snooker's stiffest test.

He has overcome Marcus Campbell and Ali Carter and looked destined for the semi-finals after racing to a 7-1 lead today in his last-eight match against fellow-Essex player Stuart Bingham.

O'Sullivan made breaks of 79, 54, 111, 60, 87, 133 and 78 in one of the finest performances he has ever produced at the Crucible.

Barring a dramatic collapse, he will secure his place in the final four tomorrow, possibly with a session to spare.

Not since Stephen Hendry won five in a row from 1992 to 1996 has a world champion successfully defended the title.

"In the last two years I've changed a lot. I'm able to not let my chimp out." - Ronnie O'Sullivan 

Although O'Sullivan has complained of feeling "jaded" at his comeback tournament, after almost a year out, that is a physical issue. Mentally he is pinpoint sharp.

O'Sullivan said: "I'm managing my emotions a lot better now. In the past there'd have been a moment in my matches against Marcus and Ali when I'd have probably thought, 'I want to be out of here, I want to go home', and I'd have not deliberately lost but subconsciously I would have given up.

"That won't happen again, none of those meltdowns will happen, no matter how frustrated I may be with myself out there. I'm able to put that on hold until the game's finished.

"Dr Steve Peters has been great to me. I've really worked hard with Steve and tried to take on board everything he's shown me and spoken to me about and obviously I'm benefiting from it massively.

"Ever since I first saw him, before the 2011 World Championship, for the whole year leading up to winning the World Championship last year, I worked really hard on trying to get hold of my emotions and my brain.

"And I'm able to not let my feelings out in front of everybody like the press and the crowd, and have people say, 'Oh, he's lost the plot'.

"Not once have you been able to see me lose the plot. Sometimes inside I feel it's tough and it's challenging, but I'm able to overcome that.

"It doesn't mean I'm going to win every match I play in. I suppose in some ways that's what endeared me to people, that I cracked up out there sometimes. They'd all want to make sure I'm all right, and the next tournament I'd come out and win and it'd be like a rollercoaster of 'which Ronnie's going to turn up'.

"In the last two years I've changed a lot. I'm able to not let my chimp out."

The 'chimp' theory is an integral part of Peters' mind management programme. The man who has played a key role in preparing Britain's Olympic cycling stars for competition teaches his patients to keep the 'chimp', bearer of strong emotions, caged in order to direct focus to the task at hand.

The World Championship will not be simply won in the head though, with O'Sullivan knowing that after almost a full year out of snooker he has to remain fluent at the table.

In Bingham, he was playing an opponent in the form of his life, who posted crushing wins over Neil Robertson, Mark Selby and Judd Trump on his way to winning the Premier League title this season.

The way he pummelled the 36-year-old was therefore a particularly impressive statement from O'Sullivan.

One factor to bear in mind is that O'Sullivan faced little resistance. Assuming he converts his six-frame cushion into victory, O'Sullivan would tackle Shaun Murphy or Judd Trump in the semi-finals, with both men, unlike Bingham, proven performers at the Crucible.

O'Sullivan has been scoring as heavily as ever, yet heading into the clash with Bingham, he said: "I believe I need to up my game in order to win.

"If someone's going to beat me, they've got to beat me. I'm going to give 100 per cent of my best and if I find a bit of form I'll be hard to beat."

Bingham, for one, would attest to that.