Novak Djokovic was left complaining to the umpire during his Rogers Cup win over Jeremy Chardy after smelling cannabis on court.
Having won the first set, Djokovic went to speak to the umpire, telling him: "Someone is smoking weed, I can smell it, I'm getting dizzy."
After winning the match, the Serb added to the press: "You can't believe how bad it was.
"Whoever it is, I hope he doesn't come back tomorrow. He's probably on the seventh sky somewhere."
It is not the first time Djokovic has had problems with the drug while in Montreal, having noticed the smell when playing a doubles match on Friday.
Commenting on the smell, he joked: "Yesterday in the doubles match, today again. Somebody's really enjoying his life around the tennis court."
Djokovic will face Andy Murray in the final on Sunday.
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