Twelve-time grand slam champion Rafael Nadal dropped just two games as he eased through his first singles match since losing in the opening round at Wimbledon.
The former world No. 1 beat 132nd-ranked Canadian Jesse Levine 6-2 6-0 in just one hour and 12 minutes in the first round of the Rogers Cup in Montreal.
The Spaniard suffered a major upset when he lost in straight sets to unseeded Steven Darcis at the All England Club in June but he was pleased to get back on track in his first singles match in six weeks.
"I didn't play a perfect match, I played well," the 27-year-old, who made a winning comeback in the doubles Tuesday, told the ATP Tour's official website.
"The conditions out there today were very difficult. I will say I did the right things to be in the next round."
Next up for Nadal, a two-time Rogers Cup champion, is Wimbledon semi-finalist Jerzy Janowicz after the Pole overcame Canadian wildcard Frank Dancevic in a match which lasted nearly two and a half hours.
British world No. 2 Andy Murray, who beat Janowicz on his way to his first Wimbledon title, was also in action for the first time since his success at the All England Club.
The two-time grand slam champion took his winning streak at the tournament to 13 with a 6-4 7-6 (7-2) win over Spain's Marcel Granollers.
Murray, a winner in Montreal in 2009 and 2010, will face Latvia's Ernests Gulbis in round two.
"I was pretty nervous beforehand," said the 26-year-old. "That was a good sign. I'm pretty ready to move forward and not think too much about Wimbledon and concentrate on the U.S. Open."
World No. 7 Juan Martin del Potro emerged victorious from a grueling encounter with Croatia's Ivan Dodig.
Argentina's Del Potro, fresh from winning a title in Washington last weekend, took the first set before the 35th-ranked Dodig fought back to clinch the second.
Del Potro fell a double break down in the third and deciding set before clawing his way back to secure a 6-4 4-6 7-5 triumph.
In the women's event in Toronto, Serena Williams recovered from losing a service game in the opening set to beat Italy's 2010 French Open champion Francesca Schiavone 6-3 6-2.
"I felt good. I felt solid," the 16-time grand slam winner told the WTA Tour's official website. "Obviously I made a few errors, but it's just my first match on hard in a really long time.
"I also played a really good player, so it was a good match. It took me a few games to adjust to her game, but it's good that she played like that because of my next opponent.
"Now I feel like I'm completely adjusted, and I feel good going into the next round."
Next up for Williams is a first encounter with Dutch ace Kirsten Flipkens, who beat her sister Venus Williams in the first round.
Wimbledon winner Marion Bartoli eased past American qualifier Lauren Davis 6-0 6-3, while 2011 French Open champion Li Na defeated Russia's Anastasia Pavlyuchenkova 6-1 6-4.
Former world No. 1 Caroline Wozniacki won the first set of a thrilling match with Romania's Sorana Cirstea, before slipping to a 5-7 7-6 (7-0) 6-4 defeat.