Ronnie O'Sullivan kept his composure in the arena but lost it in a television interview backstage after firing three brilliant centuries to knock Mark Williams out of the Betfred.com World Championship.
The three-time champion took offence at being described as his “own harshest critic” in a BBC interview and warned he would walk out if that point was ever put to him again.
But considering the Crucible audience were on their feet to acclaim his brilliant 13-10 win against Williams, while O'Sullivan saw little to enjoy from the performance, it hardly seemed like the grotesque assessment it was clearly taken to be.
“If someone says that to me again I'm going to stop the interview,” O'Sullivan told interviewer Rob Walker.
“I'm fed up with hearing that. “When you play poor snooker, you play poor snooker. I don't listen to people saying I'm my own harshest critic.
“You don't know what you're talking about.”
O'Sullivan claimed “sheer panic and desperation” inspired him to produce the five-star snooker which carried him past Williams.
Breaks of 53, 104, 75, 111 and 106 came from the cue of O'Sullivan in the deciding session, and Welshman Williams later said of his conqueror: “Everything about his game is spot on. The only person who can beat him in this World Championship is himself.”
In the press conference which followed the BBC interview, O'Sullivan played down his chances of adding to the world titles he won in 2001, 2004 and 2008.
“For a change I managed to put a few decent frames together, to my surprise,” he said.
“Out of panic and desperation I managed to find a bit of form.
“I wouldn't say it was really flowing. There's no point me getting carried away because over the years I've thrown two or three world titles away.
“I don't think my game is suited to win a world title and I've managed to win three.
“My game was never suited to the 17-day marathon, with my ups and downs. I'm all right over best-of-nines and best-of-11s but get me over the longer ones and you can be found wanting sometimes unless you're consistent.”
Williams had looked favourite for the match when he led by two frames with two frames remaining of yesterday's second session.
But then O'Sullivan's form kicked in and dazzling breaks of 66 and 72 meant he finished the evening on a high.
Williams said: “The two clearances he made from 8-6 to 8-8 were incredible. He got a little bit of the rub of the green but when you're playing that well you deserve everything you get.”
Mark Selby awaits O'Sullivan in the quarter-finals, after completing a crushing 13-5 win against Stephen Hendry.
Ali Carter joined O'Sullivan in the quarter-finals with a 13-11 victory over Joe Perry, after almost failing to take advantage of a 10-6 overnight lead.
Perry won five frames in a row to jump 11-10 ahead, but 2008 runner-up Carter fired in breaks of 104 and 82 to edge ahead and then stayed composed to win frame 24 with two scoring visits.
Former World champion Shaun Murphy defeated China’s Ding Junhui 13-10 to make the last eight last night.