HE’S had almost 25 years in professional snooker, but Cwm's Mark Williams admitted the nerves got to him like a tour rookie as he scraped into the quarter-finals of the Betway UK Snooker Championship last night.

The 41-year-old ‘Welsh Potting Machine’ just edged out Liam Highfield 6-5 in a marathon encounter on Thursday evening in York, setting up a last-eight showdown with five-time world champion Ronnie O’Sullivan in the process.

It was deadlocked at 2-2 at the interval, with Williams notching a break of 70 in the third frame, and after an 87 to go 3-2 ahead it looked like he had finally hit his stride.

But six more scrappy frames were still to come, with Williams falling 5-4 behind before coming back to win a nailbiting decider when both players missed several opportunities to clinch the match.

“I’m just happy to get over the line,” said Williams. “I don’t know why but that last red he left me to win the match, I came over and I was so nervous I couldn’t believe it.

“My leg was moving, my head was shaking, my hands were shaking and I couldn’t work out what was happening. It’s not like £200,000 was at stake or something.

“I was twitching all over the place at the end, but he was as well which helped me out a bit. I can’t remember feeling that nervous at the end since I played Stephen Hendry [in the 1998 Masters final] and we had a respotted black in the final frame.

“It’s a horrible feeling, but he’ll be very disappointed as he had a good chance to beat me there.

“There weren’t many breaks going in, but it made for a good, tense finish.

“I’m now 100 per cent in the Masters, so I think in the back of my mind that was putting a bit of pressure on me towards the end.”

Williams takes on old rival O’Sullivan this evening for a place in the semi-finals, and despite the Rocket’s immense pedigree, Williams fancies his chances.

He said: “I’m looking forward to it. I’ve had a good record against him and I think that record will continue.

“I’ve been just edged out by him a number of times, but it’s always a great occasion. He’s probably the best player ever to pick up a cue.

“He’s not the best in the world at the moment though; John Higgins is only just in front of him, but the difference is miniscule. All three of us have been going since the 90s and it’s great we’re all still in.”

Follow the UK Championship LIVE on Eurosport with Colin Murray, Jimmy White, Neal Foulds and Ronnie O’Sullivan.