World number one Novak Djokovic suffered a stunning 6-2 6-2 defeat to Jo-Wilfried Tsonga at the Rogers Cup in Toronto.
Tsonga himself is far from an also-ran in world tennis but, after 11 successive defeats to Djokovic dating back to 2010, few could have seen the result coming - let alone the emphatic manner of it.
The pair were on court for little more than an hour, Tsonga converting all four of his break points to continue his good record at a tournament where he has reached the semi-finals twice in three previous appearances.
"For me today it was great," the Frenchman told the ATP Tour website. "I played a good match, I served pretty well, I was pretty aggressive."
Tsonga will face Britain's eighth seed Andy Murray, who was given a walkover after opponent Richard Gasquet withdrew due to an abdominal illness.
Roger Federer's quarter-final place was also in doubt as he was pushed all the way before beating Croatia's Marin Cilic.
The Swiss star took the first set on a tie-break and looked set to finish the job, but Cilic saved six match points in the second before winning it - also in a tie-break.
Federer finally came through, though, wrapping up a 7-6 (7/5) 6-7 (3/7) 6-4 win in two hours and 40 minutes.
Compatriot Stan Wawrinka, the third seed, was beaten 7-6 (10/8) 7-5 by big-serving South African Kevin Anderson, who will face Grigor Dimitrov in the next round. The Bulgarian beat Spain's Tommy Robredo 7-5 5-7 6-4.
Home favourite Milos Raonic, looking to build on his win in Washington last week, battled through with a 6-3 4-6 6-4 win over Frenchman Julien Benneteau.
David Ferrer recovered from a terrible first set to beat Ivan Dodig 1-6 6-3 6-3 but fourth seed Tomas Berdych is out, beaten 3-6 6-3 6-4 by Spain's Feliciano Lopez.