John Higgins made a maximum break but still bowed out of the williamhill.com UK Championship to Mark Davis.
Forty-year-old Hastings journeyman Davis has been a professional since 1991 but could not think of any win in the last 21 years that has brought him more satisfaction than his 6-5 victory at York's Barbican Centre.
He even compared the climax to the famous finish to the 1985 Crucible final between Steve Davis and Dennis Taylor.
The match had everything, with Davis leading 5-2 after back-to-back centuries before Higgins kickstarted a fightback with his 147 in the eighth frame.
That in itself will be worth £13,500 (€16,600) providing nobody matches it over the final four days of the championship, but to millionaire Higgins it felt unimportant after he spurned a big chance in the deciding frame, missing the pink after closing to 53-49, to allow Davis in to steal it.
Three-time UK champion Higgins had recovered brilliantly after his languid start, but by the end Davis was the man looking forward to a quarter-final this evening against Welshman Matthew Stevens.
Davis said: "I was going for doubles and all sorts in the end. It was like the 1985 World Championship final."
Asked where it ranked in his victories, Davis said: "This is at the top. I've not got a good record against John at all. It's my best result for a very long time."
It was beyond 11.30pm when Davis clipped in the match-clinching pink, and Higgins could only forlornly shake his hand.
"I'm gutted," Higgins said. "Normally clearing up in the last frame I'd have done it. I didn't deserve to win that match. Who knows where the 147 came from?"
Elsewhere today, the 2008 UK champion Shaun Murphy takes on 17-year-old Belgian Luca Brecel, who recovered from 3-0 adrift to overhaul Mark King 6-4 in the second round.
Were he to go on to win the tournament on Sunday, Brecel would break Ronnie O'Sullivan's record as the youngest winner of a ranking event. O'Sullivan won the UK title event in 1993, seven days shy of his 18th birthday.
Asked if he could carry off the trophy this weekend, Brecel said: "I can win, but we'll see what happens."
They go head to head this afternoon, which is also when the all-Essex affair between Ali Carter and Stuart Bingham features.
The pick of the quarter-finals may prove to be the evening battle between Mark Selby and Neil Robertson, ranked second and sixth in the world respectively.
Selby was 3-0 down against Ryan Day in the second round but improved to prevail 6-4, while 2010 world champion Robertson was largely untroubled but had concerns over the table conditions as he beat Barry Hawkins 6-2.