Jo-Wilfried Tsonga beat Roger Federer in the Rogers Cup in a repeat of his victory at Wimbledon in June.
The Frenchman, who overhauled Federer in the last eight at SW19, advanced to the quarter-finals in Montreal with a 7-6 (7-3) 4-6 6-1 victory.
World number one Novak Djokovic beat Marin Cilic 7-5 6-2 to gain his 50th win of the season and set up a match against Gael Monfils.
Andy Murray reached the quarter-finals of the doubles with his brother Jamie.
Murray, defeated in the first round of the singles by Kevin Anderson, kept his tournament alive as the pair beat Eric Butorac and Jean-Julien Rojer 6-2 2-6 10-8.
With world number two Rafael Nadal already out of the tournament after his defeat at the hands of Ivan Dodig, fifth seed Monfils is the highest-ranked player after Djokovic left in the competition.
Tsonga, who recovered from the loss of the second set to convert two of six break points in the decider, believes the men's game is becoming more competitive.
"All the players keep improving. I believe that no player can be spared. Look at Rafa who lost, and Murray.
"The only one remaining above everybody else is Djokovic."
Sixteen-time Grand Slam winner Federer, who turned 30 on Monday, admitted he thought he may be vulnerable to another defeat by Tsonga.
"I thought if he was going to play well again and me not at my best, he could do it again. He's confident right now," he said.
Djokovic, speaking before Federer's defeat, admitted he had been surprised to see Murray and Nadal make early exits.
"It's expected from them and from all of us top players to advance to the last stages of a tournament, but it happens," said Djokovic.
"This is tennis. Both of their opponents have played great matches, and that's it. You move on."
The Serb has lost just once - to Federer in Paris - so far this year.
Elsewhere in the singles, seventh seed Tomas Berdych beat Ivo Karlovic 6-3 7-6 (7-2) and 14th seed Stanislas Wawrinka defeated Kevin Anderson 6-4 4-6 6-4.
Croatia's Ivan Dodig could not build on his stunning win over Nadal, with Serb Janko Tipsarevic proving too strong in a 6-1 6-4 victory.
Monfils won two tie-breaks to overcome Viktor Troicki 3-6 7-6 (7-0) 7-6 (7-5), while Nicolas Almagro and Mardy Fish were victorious over Richard Gasquet and Ernests Gulbis.