Seven-time champion Ronnie O’Sullivan was dumped out of the UK Championship by Switzerland’s Alexander Ursenbacher in Milton Keynes.

The world number 66 produced a thrilling display of attacking snooker then held his nerve to repel an O’Sullivan comeback and edge a 6-5 second round win.

It was Ursenbacher’s second win over O’Sullivan in two career meetings, having also triumphed in their match at the Welsh Open last year.

Despite an error-strewn display, O’Sullivan looked set to dredge up a place in the last 32 when he turned a 4-2 deficit into a 5-4 lead.

Ursenbacher’s policy of all-out attack, which had served him so well in the first part of the match, began to go astray as he neared the winning line.

But a badly overcut red saw a plainly exasperated O’Sullivan miss his own chance to seal victory and extended his agony into a decider.

Ursenbacher pounced with a pair of brilliant long reds which earned him his chance to wrap up the frame and with it easily the biggest win of his career.

O’Sullivan told Eurosport: “He played really well, he deserved his victory. I think I did well to get five frames, I think the scoreline flattered me to be honest – it should have been 6-1, 6-2 really.”

Asked if he was tired, O’Sullivan said: “No, I’m not making any excuses” and added: “He kind of kept giving me chances and I got back into it, but really he was much the better player. My performance just wasn’t good enough to beat someone that plays that well.

“I’ll probably have to sleep on it and have a think about it because I don’t really know what happened out there other than I’m out.”

Regarding the aggression in Ursenbacher’s play, O’Sullivan said: “That’s how he always plays – I thought he was quite conservative today, normally he goes for even more. Today I thought I was more the aggressor and he was more like trying to keep it tight.

“But he swings – if he was a boxer you’d have to be ducking all the time because if one of them hits you it is like bombs. He can play.”

Ursenbacher said: “That was a very big test for me – I knew I could beat him in a best of 11 and I had absolutely nothing to lose so I had to fancy the job.

“Ronnie is a great, great player so you know what you’re up against, but I just tried to treat it like a practice match and focus on the next ball.

“My goal was just to play Ronnie, and this has opened so many doors for me that my goal is to win it now.”

Sunday’s afternoon session also included Mark Selby progressing with a 6-1 win over Liam Highfield.

In the evening session, world number seven Shaun Murphy suffered a shock 6-1 loss to Elliot Slessor, ranked 49 places below him.

Kyren Wilson advanced with a 6-2 victory over Mark Joyce and Mark Williams defeated Thailand’s Akani Songsermsawad by the same scoreline.