Ronnie O'Sullivan's verdict after inflicting another defeat on Ali Carter was that he was already feeling the strain of the Betfair World Championship.
Fellow Essex player Stuart Bingham was the latest player lined up to attempt to halt the charge of the defending champion, who finished off in auspicious style as he made it 13 wins from 13 matches against Carter.
Last night saw O'Sullivan race from 9-7 ahead to a 13-8 victory against February's German Masters champion, proving that even with hints of rust in his game he is capable of slaying recent tournament winners.
Breaks of 88, 106 and 89 in the final three frames suggested O'Sullivan would be difficult to stop as he bids to become the first player since Stephen Hendry in 1996 to retain the world title.
O'Sullivan, who beat Carter in last year's final and also to land the 2008 title, said: "I'm pleased I came through it but it's not going to get any easier now.
"I feel a lot more tired and jaded than I did coming into this tournament last year."
Carter is convinced O'Sullivan, playing after almost a year off, can carry off the title.
"If his head doesn't fall off, yes he will," Carter said. "But we all know if his head falls off anyone can beat him."
Bingham has struggled to make a World Championship impact since marking his debut in 2000 with a stunning first-round win over defending champion Stephen Hendry.
But the 36-year-old from Basildon posted a 13-10 win over Mark Davis yesterday to set up the O'Sullivan showdown, and this season's Premier League champion is unlikely to be a pushover.
World number eight Bingham said: "I've got nothing to lose, all eyes are on Ronnie.. Hopefully it'll be like a break-building feast."
O'Sullivan and Bingham feature in the top half of the draw, alongside Shaun Murphy and Judd Trump who were playing morning and evening sessions today in their heavyweight quarter-final.
China's former UK and Masters champion Ding Junhui appears to be the outstanding candidate to come through the bottom half of the draw, and he was tackling Kent's Barry Hawkins today.
Ding dazzled as he came from 6-2 behind to beat Mark King 13-9, firing four centuries and seven further breaks above 50 in the match.
This could be the year that Sheffield-based Ding finally reaches a Crucible final, after frequent underachievement at the World Championship, and King was bowled over by how the 26-year-old performed, particularly when dominating the middle session of their contest.
King said: "He was on a different planet and when he's hitting the ball like that I don't think anyone can get near him, even Ronnie O'Sullivan."
Chester's two-time former ranking event winner Ricky Walden and 21-year-old Welsh qualifier Michael White were going head-to-head today in the other quarter-final.