TORONTO, ON - AUGUST 08: Rafael Nadal of Spain serves against Benoit Paire of France during a 2nd round match on Day 3 of the Rogers Cup at Aviva Centre on August 8, 2018 in Toronto, Canada. Vaughn Ridley/Getty Images/AFP

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 percent 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 quarterfinals 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 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.