Williams beats Higgins in stunning Crucible black-ball finish

Three-time winner Mark Williams held off a spirited John Higgins fightback to win a Crucible classic 13-12 on the black as he reached the semi-finals of the World Championship.

Resuming at 8-8 on Wednesday, Higgins was initially left to rue costly misses in each of the first four frames as winner Williams reeled off all four with three half-centuries along the way.

Williams, 50, who had trailed 5-1, took the 20th frame but was then largely confined to his chair as four-time champion Higgins delivered a stirring response from 12-8 down.

The 49-year-old, who appeared to be labouring, suddenly found his rhythm and compiled breaks of 94, 114 and 67 to set up a dramatic finale.

Both players had opportunities to clinch a tense final frame but when Higgins rattled the jaws of the corner pocket on the blue, the Welshman capitalised to become the oldest player to reach the last four since 52-year-old Ray Reardon in 1985.

"Unbelievable game, unbelievable finish. The blue I played was probably one of my best shots for many years," Williams told BBC Sport.

"What a blue...balls of steel. It was tough a shot. I could have gone in-off. I could have over cut it. I just went for it full-blooded.

"There was not one bit of nerves, maybe I've only had them a handful of times in my entire career."

Williams' victory over Higgins means he will face Luca Brecel or world number one Judd Trump in the semi-finals.

While world number six Williams has generally held sway over his fellow 'Class of 92' rival in Sheffield - winning five of their six meetings - it was still a first loss in a decider for Higgins at the Crucible since 1996.

However, the prospect of it living up to the thriller they served up in the 2018 final, in which the Welshman eventually triumphed 18-16, appeared unlikely to materialise after the first four frames of the morning.

While Williams said he belted out 'Delilah' by Tom Jones to inspire him before arriving, Higgins had appeared out of sorts and out of rhythm until the mid-session interval and only when he reappeared did he resemble the player that recently won the World Open and Tour Championship.

"I was poor the first four frames, but after the interval I had nothing to lose and played maybe the best four-frame burst of the whole event," said the Scot.

"I had my chance. If I pot the brown and roll through, maybe the blue is unmissable, but you are under that much pressure.

"It was an incredible atmosphere. I am devastated right now but the atmosphere we got in there is why we keep playing the game."

In Wednesday morning's other quarter-final, Ronnie O'Sullivan maintained his four-frame lead over Si Jiahui and will take a 10-6 lead into the concluding session at 19:00 BST.

Leading 6-2 overnight, 'the Rocket' traded frames with world number 13 Si to head into the mid-session interval at 8-4.

O'Sullivan, who is bidding for a record eighth crown in the modern era, went 9-4 up when Si missed a red to the left middle when 43 points ahead with 43 remaining.

Despite that setback, the 22-year-old from China, who had compiled a century in the 10th frame, took the next took with runs of 61 and 52.

O'Sullivan, though, showed all his experience to take the 16th frame with a break of 64 to restore a healthy cushion.

It leaves the Englishman on course for a a record-extending 14th appearance in the semis.