Andrey Rublev pulled off a shock in the Canadian Open quarter-final, knocking out an ailing Jannik Sinner in three sets. (More Tennis News)
The world number one pulled out of the Olympics due to illness and appeared to be struggling with a recurring hip injury as he was beaten 6-3 1-6 6-2 in Montreal on Saturday.
In a rain-hit match, Rublev took the first set before Sinner rallied to force a decider but he could not retain his momentum as the Russian snapped his eight-match winning streak on hard courts.
"It was a really great match of mine. I was playing really well today, and I'm happy that I was able to win," Rublev said.
"I don't know, not much to say, because I still, for the moment, really don't understand what's happening, because Jannik is an amazing player and he's playing unbelievable for the past two years.
"I was just hoping that I would be able to fight with him, to show great tennis. In the end, I think we had a lot of great rallies, a lot of long rallies.
"To be able to win this kind of match, of course, it's always special. I needed those matches, especially after some bad moments this year. So, of course I'm happy."
Since the start of the 2020 season, Rublev is now one of four players to defeat the ATP's number one on multiple surfaces, along with Novak Djokovic, Daniil Medvedev and Holger Rune.
Meanwhile, Alexander Zverev prevailed in straight sets against Rune earlier on Saturday to reach the last eight with a 6-3 7-6 (7-5) win.
Excluding team events, Zverev is now in an 11th ATP-level quarter-final in 2024. It is the most of any player this season, while the German (11) is one of just two to reach 10+ ATP event QFs this year, along with Sinner (10).