Novak Djokovic moved into the third round of the Rogers Cup with a straightforward 6-3 6-4 success over Peter Polansky on Wednesday.
And 17-year-old Felix Auger-Allissiame made a strong statement in a comfortable 6-4, 6-3 win over Lucas Pouille.
"I thought I found pretty good accuracy and angles with the first serve, and also my second serve worked pretty well".
He was replaced by the 27-year-old Bosnian who was outclassed early, but troubled the 4-time Canadian champ in the second, breaking him twice late, before falling.
Nadal will face Stan Wawrinka in the round of 16 after the Swiss rallied to beat Hungarian Marton Fucsovics 1-6 7-6 (2) 7-6 (10).
It was a masterclass in Toronto, where world number one Nadal came out on top 7-5 7-6 (7-4) after more than two hours of scintillating tennis.
Polansky said of Djokovic, "He raises his level on the big moments".
As the second round got under way, there were delays-not for the first time-as rain storms passed over Toronto, but also news of the withdrawal of No3 seed Juan Martin del Potro with wrist problems. 'That loss matured me', Tsitsipas said aout the match against Zverev.
Eighth-seeded John Isner, the American who won at Atlanta two weeks ago, beat France's Pierre-Hugues Herbert 7-6 (3), 6-2.
"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".
He next faces Wimbledon runner-up and fourth seed Kevin Anderson who defeated Ilya Ivashka of Belarus 7-5, 6-3 to also make the last-eight.
Tsitsipas, who turns 20 on Sunday, relied on his serve and forehand combination to get by Djokovic, who was competing in his first tournament since collecting his 13th grand slam title at the All England Club last month. "I think I did a good job of finishing the job today".
Pavlyuchenkova is leading 4-3 with the match due to resume tomorrow.
U.S. Open champion Sloane Stephens, seeded third, routed local favorite Francoise Abanda 6-0, 6-2.
A couple of single-handed backhands in the shape of charismatic #NextGen top-30 teenagers, Canadian Denis Shapovalov and Greek Stefanos Tsitsipas, got plenty of cheers with their straight-sets, first-round wins.
"The main goal of the tweet was because I was disappointed, obviously not for myself, but because there was so many fans and friends that wanted to come watch me on centre court and they weren't able to", Shapovalov said.
Defending champion Elina Svitolina of Ukraine, seeded fifth, led Mihaela Buzarnescu 6-3, 6-7 (5-7), 4-3 when the Romanian retired because of an ankle injury.