revealed he was inspired by Tom Jones after he held his nerve to pip old rival on the final black in a classic. It was a quarter-final billed as a heavyweight clash between two Class of 92 all-time greats and it certainly lived up to the hype.

Three-time winner Williams, who turned 50 last month, left Higgins feeling blue with a dramatic 13-12 decider epic. Herculean Higgins, a four-time Crucible champion, hauled himself from 12-8 behind to force a fitting final-frame shoot out, but as Welsh wizard Williams became the oldest Crucible semi-finalist for 40 years after late compatriot Ray Reardon - who was 52.

Asked how he held himself together, sixth seed Williams quipped: "Balls of steel."

They were the same three words that cracked up host and pundit Ken Doherty when he sat down to discuss the match.

And Williams, who walks out to Jones' hit Delilah, added: "I was really drained this morning. We had two tough sessions. Finished late last night, and back on this morning.

"I was feeling really tired and drained in there. I just kept playing Delilah on my phone and Boy from Nowhere from Tom Jones over and over, just to try and keep me with it because I was really, absolutely, mentally, really drained. God knows how many times I repeated them songs.

"It was an unbelievable game, unbelievable finish. The blue I played was probably one of the best shots I played for many years to come that good on the pink. What can I say? There wasn't one bit of nerves or shaking. I don't really get that. I've only ever had my hands shaking or my heart pumping a handful of times in my career. I don't know why."

After battling from 5-1 down to 8-8 overnight, Williams made it 11 frames out of 14 to lead 12-8. But world No.3 Higgins heroically hauled himself back in contention with breaks of 114, 94, 67 and 49 to force a decider. Higgins missed a blue for the match and watched Williams pot blue, pink and black to reach an eighth semi-final.

The emotional Scot held back tears and said: "It's heartbreaking. I had my chance. I had the blue. I was totally calm right up to that blue. I was thinking I couldn't see the bag. You're just guessing at that point and it's difficult and I missed it.

"It's difficult. It's 12-12 in the quarter-final of the , it's probably the most pressurised situation in your career. I think I've been one of those players who's always had a good perspective. Sometimes when I lose in front of you guys it's raw. I know what's more important in my life and she's over there [wife Denise]. I know that.

"I lost and I've devastated right now. It's what happens. I go home and the family and loved ones will pick you back up and you get on with life. I can't be too down on myself. I've lost a classic game there to an unbelievable champion."