Mark Selby sent red-hot favourite Ronnie O'Sullivan crashing out of the Betfred.com World Championship tonight.
Selby has become an irritant to three-time world champion O'Sullivan after making a habit of fighting back to beat him in major finals.
The Leicester player won 9-8 from 8-5 down against O'Sullivan in the 2008 Welsh Open and then 10-9 from 9-6 behind at January's Wembley Masters.
This was another example of his refusal to accept looming defeat, as Selby won the final four frames to earn an 13-11 victory.
After the Masters defeat at the start of the year O'Sullivan suggested neither he nor Selby would be capable of winning the world title due to their shared bold, attacking approach.
That may still hold true this year, but it was a careless assessment from O'Sullivan and one Selby would love to disprove over the bank holiday weekend.
Selby began the evening session 9-7 behind but knowing that O'Sullivan, who was curiously booed by a minority of spectators as he entered the arena, would be expecting him to fight all the way.
They had started the day at 4-4 but O'Sullivan threatened to run away with the afternoon session, winning five of the first six frames with breaks of 92, 89, 86, 117 and 52.
He was playing unbelievably well for a player who has looked disinterested for much of the tournament.
The flurry of high breaks made the next two frames critical, and Selby took both with runs of 104 and 62 to begin the fightback.
He also won two of the first three frames of the evening to cut O'Sullivan's lead to 10-9, and was well placed in the next when he missed a routine black.
Selby struck the white so hard that the black jumped out of the pocket and six inches into the air before careering down to the baulk cushion.
For O'Sullivan the chance was an unexpected gift and he raced to 75 to take the frame.
That meant Selby needed four of the next five to reach the semi-finals.
He made it three from four required thanks to a smooth break of 108, and then two from three after a scrappier frame.
O'Sullivan looked on edge, the afternoon form was long gone.
Both men had chances and missed easy balls in the 23rd frame but Selby's 46 break proved decisive as he swept into the lead.
O'Sullivan was in with a break of 36 at the start of the frame he needed to win to force a decider, but he broke down and Selby soon had a match-winning chance.
He needed more than one visit to the table to make sure, but when he rifled in the brown O'Sullivan rose from his seat to shake his conqueror's hand.
O'Sullivan said: ‘I take matches like that on the chin now.’
He hinted at retirement, not for the first time, before stressing he would be back playing again next season.
Asked if he needed snooker as much as the game needs him, he said: ‘Not really, no. I love the game and it's been great to me.
‘I'll always be involved in snooker because it's in my blood but I don't need it.
‘But it's like a drug and I know I will miss it, and I'll always think 'What if?'.
‘I've had 17 years of trying and hoping and thinking that my game can turn around, so I know
‘I've given it my best and I can't give it any more than I have done.’
Asked specifically if he would play next season, he said: ‘Of course, I hope so.’
The 34-year-old was resigned to defeat long before Selby potted the brown in the final frame.
’You get to know your own engine. You're sitting there thinking that anything can happen but inside you know how it's going to pan out,’ said O'Sullivan.
In tonight's other quarter-final England's Ali Carter edged out compatriot Shaun Murphy in the final frame winning 13-12.
