A physically exhausted Ronnie O'Sullivan has revealed he was "absolutely gone" before suffering a shock early exit at the UK Championship – and plans to learn from his mistakes at the Masters in Milton Keynes.
The six-times defending world champion suffered a 6-5 defeat to world number 62 Alexander Ursenbacher in the last 64 of the UK last month despite watching his Swiss opponent contribute a highest break of only 67 over 11 frames.
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O'Sullivan has explained how his addiction to running contributed to a shock downfall at the sport's second biggest ranking event that he later described as "embarrassing".
The record seven-times Masters winner admits he will only stay in the running at snooker's major tournaments in the year ahead by cutting back on the hard yards away from the table.

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"That week, I managed to get 55 miles in," said O'Sullivan ahead of his first-round match with 2011 champion Ding Junhui at the Marshall Arena. "I only managed 40 even when I was running brilliantly 10 years ago.
"I've managed to build my volume up. I don't run as fast now, but I go for a bit longer.
"I ended up doing two 11 milers in one week which cranked the miles up, but towards the end of it I was absolutely shattered.
I was gone at the UK, absolutely gone. I was like 'oh dear, what have I done'. I don't make excuses because the other guy played well, but physically I'd overdone it.
"If you speak to an athlete that's overtrained, it's like a weird sort of tiredness.
"You end up with a sort of a 36 or 48-hour bug so after that I thought I'd better go back to 36 or 40 miles because I had a couple of tournaments I wanted to play in and play well," added O'Sullivan, who is 5-2 favourite with tournament sponsors Betfred for an eighth Masters title with world number one Judd Trump out due to coronavirus and former winners Neil Robertson and Mark Selby both knocked out.
"Like anything, if you want to be good at it, you've got to be obsessive about it.
"When it's tournament week, I've got to learn that it's okay to do five or six miles in the morning, but I don't need to run 10 miles every day.
"Once I get sucked in, I love it."

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O'Sullivan – whose autobiography is aptly titled Running – has revealed he has been inspired by 2009 Formula One world champion Jenson Button's approach to the triathlon that he married with his trophy-laden career behind the wheel.
Fellow British sporting icon Button won 15 races in F1 between 2000-2017, but once commented that "I am probably just as nervous, probably more nervous in a triathlon than an F1 race".
"My big priority is my running. I've got into half decent shape now," said O'Sullivan. "When I started nine months ago, I was jogging, but now I'm running seven or eight miles which is nice.
"I'm buzzing about that so my goal is to run some 10 milers, some half marathons, a bit like Jenson Button used to do with the triathlons. I want to take it seriously.

Ronnie O'Sullivan at the Masters.

Image credit: Eurosport

"I feel like I've got my injuries behind me so now it's about how you prepare in the same way you prepare for the World Championship or the Masters in snooker. You've really got to be on it day in, day out."
O'Sullivan has quit smoking in his bid to help his longevity after becoming the second oldest winner of the world title in the Crucible era at the age of 44 behind fellow six-times champion Ray Reardon with an 18-8 win over Kyren Wilson last August.
He remains the youngest winner of the Masters when he was 19 in 1995, but could become its oldest winner in the 47th staging of the sport's biggest invitational event.
The record 37-times ranking event winner has confirmed he plans to compete at the Masters, World Championship, Players Championship and Tour Championship in a schedule of at least "eight or ten" events in 2021 as he bids to keep pace with the field.
"My main focus at my age is good health. I'm 45 and haven't smoked for nine months because of the running," he said. "I'm enjoying the benefits of running. My mental health is in a much better place, I don't smoke and I just feel a lot happier.
"That is number one. That has to stay no matter what. Other than that, I want to try to play 10 events in the whole year. I don't enjoy playing week in, week out.
"I don't want to do that so for me I want to play between eight and ten events maximum spend more time at home and the events that I do play in make sure I can meet the local running club so I can go out running and train like I would do at home.

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"That's really the goals for me. I'll play the Masters and see what happens with the other tournaments. I'll probably play the Coral events that I've qualified for and the World Championship.
"All the other ones, I'll decide later on whether I feel like I need the practice or not."
Desmond Kane

2021 Masters scores/schedule

First round
Sunday January 10
  • Kyren Wilson 6-2 Gary Wilson (1pm)
  • Joe Perry 2-6 David Gilbert (7pm)
Monday January 11
  • Stuart Bingham 6-4 Thepchaiya Un-Nooh (1pm)
  • Shaun Murphy 6-4 Mark Williams (7pm)
Tuesday January 12
  • Neil Robertson 5-6 Yan Bingtao (1pm)
  • Mark Selby 3-6 Stephen Maguire (7pm)
Wednesday January 13
  • Ronnie O'Sullivan v Ding Junhui (1pm)
  • John Higgins v Mark Allen (7pm)
Thursday January 14
  • David Gilbert v Kyren Wilson(1pm)
  • Stuart Bingham v Shaun Murphy (7pm)
Friday January 15
  • Higgins/Allen v O'Sullivan v Ding (1pm)
  • Stephen Maguire v Yan Bingtao (7pm)
Saturday January 16
  • TBC v TBC (1pm)
  • TBC v TBC (7pm)
Sunday January 17
  • TBC v TBC (1pm, 7pm)
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