Top seed Rafael Nadal blew past patchy Frenchman Benoit Paire 6-2, 6-3 on Wednesday to begin his quest for a fourth Canadian trophy at the Toronto Masters.
The world number one Spaniard was untouchable as he schooled Paire for the fourth time without a loss, taking 74 minutes as he broke six times.
Nadal won the event in 2005, 2008 and 2013.
"I was not at my 100 per cent today," Nadal said. "It's true that I did good work here the last five days, but at the same time it's true that I didn't work very hard at home.
"So the first match is an important victory for me, for my confidence. It's important that I have another match tomorrow too. So just try to keep going.
"I played a solid match, in the second set I had some troubles, but my return worked well. It was more about the mistakes from the baseline."
The 32-year-old will bid for the quarter-finals here for the first time since 2015 when he plays Stan Wawrinka, who staged another fightback in three sets, beating Marton Fucsovics 1-6, 7-6 (7/2), 7-6 (12/10).
Defending champion Alexander Zverev, seeded second and winner at the weekend in Washington, also advanced easily beating Bradley Klahn 6-4, 6-4.
Former top-ranked Novak Djokovic, a four-time champion, sent Canadian Peter Polansky to a 6-3, 6-4 defeat.
Two generations of local players split the difference with Milos Raonic, 27, heading out while teenaged gun Denis Shapovalov moved on.
American Frances Tiafoe beat Raonic 7-6 (7/4), 4-6, 6-1 in a match hit by a weather interruption of more than two and a half hours.
Teenaged prodigy Shapovalov eliminated Italian 14th seed Fabio Fognini winner last weekend in Los Cabos, 6-3, 7-5.
Djokovic expressed support for the new 25-second shot clock innovation designed to cut down on time wasting between points.
"I'm pretty comfortable with it -- it's good to have shot clock in the tournaments prior to the US Open."
The 13-time Grand Slam title winner has now won 21 of his last 24 matches after a rollercoaster start to 2018 which saw him go 6-6.
Djokovic, the winner of 30 career Masters titles, will next face rising Greek Stefanos Tsitsipas, who beat seventh seed Dominic Thiem 6-3, 7-6 (8/6).
It was the second straight opening defeat for the Austrian, who also last last week at home in Kitzbuehel; he reportedly arrived carrying a virus.
Wimbledon semi-finalist John Isner defeated Pierre-Hugues Herbert of France 7-6 (7/3), 6-2.
Third seed Juan Martin del Potro was forced to withdraw prior to his opening match due to a left wrist injury.