Ronnie O'Sullivan started his UK Championship campaign against Daniel Wells on one leg but will withdraw from the tournament if he feels no let-up from his broken ankle by the weekend.

The Rocket beat plucky amateur Wells 6-2 at York's Barbican Centre, coming through after a tricky first half of the match.

O'Sullivan was not the only walking wounded at York, with two-time world champion Mark Williams beating Steven Hallworth 6-1 despite a muscle injury picked up during weight training.

1997 world championship winner Ken Doherty beat England's Mitchell Mann 6-2, Marco Fu avoided a shock loss to Ahmed Saif while Mark Davis, Liam Highfield, Luca Brecel, Robin Hull , Jack Lisowski and Jimmy Robertson also progressed.

In the evening session, defending champion Neil Robertson waltzed through 6-0 against Joe O'Connor, while Stephen Maguire beat Lu Ning 6-2. 

Oli Lines failed to follow his father Peter into the next round after succumbing 6-2 to Yu Delu, while 2008 champion Shaun Murphy beat veteran James Wattana 6-3.

It has often been said that five-time world champion O'Sullivan could win a snooker match with all manner of handicaps enforced, and playing on a broken left ankle after a fall while running backs that up.

But for all the admirable courage shown, O'Sullivan admitted afterwards he will not start Sunday's second-round match against Leeds veteran Peter Lines or Northern Ireland's Joe Swail if he has felt no improvements.

"The injury is disappointing, a broken ankle. It is not too comfortable and I didn't enjoy any of that," the 38-year-old said at his post-match press conference.

"I thought I would give it a go but if it doesn't improve I'm not sure I'm going to play my next match.

"I can't get on the shot properly, I'm hobbling around, it's swelling up and it's painful.

"I've taken all the painkillers, done all I can do, and if it's not better by Sunday I probably won't play."

"I've taken all the painkillers, done all I can do, and if it's not better by Sunday I probably won't play" - Ronnie O'Sullivan

A withdrawal from the sport's most popular player would be a severe blow for the tournament but would, even at such an early stage, open the field up.

O'Sullivan has looked near-unbeatable since his return to the main tour after a self-imposed year-long exile, and he was a short-priced favourite to win a fifth UK title.

The Essex man has cited running as one of the key reasons why he has finally beaten the mental troubles that plagued his career.

He revealed in his recent autobiography, entitled 'Running', that he had contemplated quitting snooker all together and dedicating himself to athletics.

Now, though, he says he is going to put the trainers away until he retires.

"I am absolutely gutted. I am enjoying my snooker more than ever and to do that through running - I am really angry with myself," he said.

"I am so annoyed at myself. I think I will probably stop running now until the end of my snooker career because you can't do this.

"It's the third time I have broken my foot. I fell over in the forest. I was running with my mate and he'd asked me what time I was doing on the run. I looked at my watch and I just lost my footing and I slipped.

"That was it. Partly his fault, partly my fault and I am frustrated with myself because I am a snooker player, not a runner. I just shouldn't do it. It is really frustrating."