John Higgins admitted he gift-wrapped victory to his bogeyman Mark Davis after bowing out in the second round of the Bank of Communication Shanghai Masters.
Scotland's former four-time world champion has suffered a catalogue of losses to Davis, with the Englishman most notably knocking him out of the UK Championship and World Championship last season.
And it was a painfully familiar story for Higgins, as 41-year-old Davis maintained the form that saw him win the 6-Red World Championship earlier this month to win 5-1, setting up a quarter-final against China's Xiao Guodong.
Davis had a best break of 76 and said: "John wasn't at his best today but any time you beat him is a great result. I'm really pleased to be in the quarter-finals. I know I'm good enough to win an event like this although I haven't been to a final in 23 years."
Higgins accepted his performance was well short of what was required, as he said: "I didn't play very well.
"Mark has been in form for a couple of weeks so it was a tough match. I didn't put him under any pressure.
"When you lose so many times to one player it's in the back of your mind a bit. But he always plays very well against me so I've got no complaints."
Xiao staged a fine recovery from 3-1 behind to knock out Leeds veteran Peter Lines 5-3.
If world number 39 Xiao is a surprise name in the quarter-final line-up, a greater shock has been provided by 100th-ranked potter Kyren Wilson.
At his first ranking event, Wilson followed up his first-round win over Stuart Bingham - eighth in the world - by eliminating number 11 Marco Fu with a 5-3 win.
"I know I'm good enough to win an event like this although I haven't been to a final in 23 years" - Mark Davis
He peppered the match with useful breaks, including a 133 in the fourth frame, and the 21-year-old said, according to worldsnooker.com: "I'm absolutely buzzing, it's a bit of a fairy tale. I have beaten two fantastic players. I'm very hungry, very young and I want to win."
At the last-eight stage Wilson will tackle Michael Holt, the 35-year-old from Nottingham who is targeting his first major semi-final. Holt showed impressive resolve in edging out Martin Gould 5-4.
Ding Junhui also won a deciding frame to see off Shaun Murphy and give China a second player in the last eight.
Murphy could consider himself unfortunate after firing breaks of 86, 62, 102 and 84 in their evening tussle, but Ding inched over the winning line.
"Shaun was hard to beat," Ding said. "He managed to score heavily whenever he was behind."
The 2010 world champion and current world number one Neil Robertson awaits Ding in the last eight on Friday, after a 5-3 win for the Australian against England's Mark King.
Mark Selby set up a clash with World Championship runner-up Barry Hawkins after recovering from 4-2 adrift to sneak a 5-4 win over Robert Milkins. Hawkins beat Wales' Ryan Day 5-2.