Novak Djokovic began his bid for a fifth Rogers Cup crown with a straight-sets victory over Bosnia’s Mirza Basic.
Djokovic, the Wimbledon champion, won 6-3 7-6 (7-3) against Basic, who was a late replacement for injured South Korean Chung Hyeon.
Thirteen-time Grand Slam champion Djokovic will face Canada’s Peter Polansky in the second round.
Elsewhere, wildcard Stan Wawrinka beat 16th seed Nick Kyrgios 1-6 7-5 7-5 and Kei Nishikori lost to Robin Haase.