Ronnie O'Sullivan revealed he was still ravaged by self-doubt despite completing a stunning demolition job on Ali Carter to secure his place in the second round of the World Snooker Championship at the Crucible.
The seven-time champion fired three centuries and two more breaks over 50 as he took just 67 minutes to turn a tight and error-strewn overnight 5-4 lead into a stunning 10-4 triumph over the double former finalist.
O’Sullivan’s display made a mockery of his recent period of inactivity, having arrived in Sheffield without a tour match to his name since he stuffed his cue in the bin after crashing out of the Championship League in January.
But appearances can be deceptive and the 49-year-old said he had been plagued by thoughts that he had made the wrong decision since he committed to taking his place in the tournament in the middle of last week.
"I thought, what am I doing, coming here and exposing myself, imploding out there, having a meltdown – all that went through my head," admitted O’Sullivan.
"I was a bit scared about playing. It is a daunting venue to play at anyway, but it’s just about getting on the bike again and playing. I’m really happy that I’ve done it, even if I’d lost it didn’t matter – I’ve made the breakthrough now."
Carter had done well to pull within one by the end of Tuesday’s opening session, but he failed to score a point in the first two frames upon the resumption as O’Sullivan dispatched breaks of 59 and 117 to extend his overnight lead to 7-4.
Carter blew it again in the 12th frame, running out of position on 28, and, clearly in no mood to hang around, O’Sullivan produced a clearance of 74 followed by further centuries either side of the interval to complete his win.
O’Sullivan’s performance saw him surge to second-favourite for the title with the bookmakers, but he continued to talk down his chances, insisting: "My expectation levels were to maybe get a few frames and see where I go from there.
"I feel like I’ve had a victory by just winning a match, and it is all part of the rebuilding process."
Carter’s qualification for the Crucible is likely to prove enough to seal his place back in the top 16 next year.
He said: "At the end of the day I was playing the greatest player of all time. He could have had 10 years out and still have come here (and won) – he’s a freak."
Next up for O’Sullivan will be Pang Junxu, who became the sixth and final Chinese player to reach the last 16 after completing a 10-7 win over his compatriot and 12th seed Zhang Anda.
The 25-year-old was beaten 10-7 by O’Sullivan on his Crucible debut two years ago but has improved since and reached his second ranking semi-final at the Northern Ireland Open in October.
"The pressure was huge at the start and I didn’t perform well in the first session," Pang said. "But after falling behind, I relaxed and managed to play better.
"I think I have a chance to win. You learn everything from playing (against top players). Their shot selection, their response, and how to handle pressure – there’s so much I can learn from them."

Shaun Murphy believes he is well-placed to become a multiple world snooker champion after cruising through this year's first round with a 10-4 win over qualifier Daniel Wells.
The 42-year-old admitted he felt his days of contending for major titles were numbered after a decade-long 'triple crown’ drought that followed his first Masters title win in 2015.
Murphy credits his link-up with another former champion, Peter Ebdon, with sparking an impressive mid-career revival that culminated in him sweeping to his second triumph at Alexandra Palace at the start of this year.
Murphy said: "The hunger and desire never goes anywhere, but sometimes you can just lose your way in life and sport and certainly working with Peter has helped me refocus on the things that make a difference.
"Champions don’t think like everyone else, and I think for a little while I’d started to think like everyone else. I’d forgotten what it was like to win the big ones, and thought I’d become a bit of a draw-filler in the majors.
"As far as the big tournaments were concerned, I thought those days were gone. But winning the Masters and my work with Peter has totally changed that. I’ve had a complete 180. Whether it works this week or not, I don’t know, but I believe again and I think that makes me dangerous."
Murphy, who won his world title as a qualifier in 2005, was close to his flamboyant best against Wells, a Crucible debutant who far from disgraced himself as he hit three centuries including a nerveless clearance of 131 in the second frame of the match.
Murphy fashioned a 7-2 overnight lead and despite taking the opening frame of the day he was denied a swift finish by consecutive knocks of 115 and 68 from Wells.
A clearance of 133 in the 13th frame – Murphy’s third hundred in a high-quality clash that yielded a total of 14 half-centuries or better – nudged him closer to the finish line, and a subsequent 71 finished the job and set up a last 16 meeting with either Judd Trump or Zhou Yuelong.