The men's clashes in Montreal were headlined by a showdown between No. 2 seed Roger Federer and Spanish challenger Roberto Bautista Agut, while a rain-filled women's slate in Toronto featured a compelling matchup between Caroline Wozniacki and No. 1 seed Karolina Pliskova.
Federer hammered five aces, made just two double faults and won 81% of his first serve points in the 68-minute centre court match.
Federer grabbed a second service break late in the third set to effectively seal the victory and improve to 17-0 lifetime against the 35-year-old Spaniard.
Second-seeded Roger Federer continued his mastery over 12th-seeded Roberto Bautista Agut of Spain with a 6-4, 6-4 victory.
"But, you know, I played in five finals this year".
Zverev has now won his last 9 matches after winning Washington last week, and 10 straight in Masters events following that Rome title.
"If I don't save those match points in the first match, there's no chance of being here". "Sometimes I played them maybe 30 or 40 times. I think it is because I went more to the net, which was not possible against Ferrer", analyzed Federer.
Holland's world No.52 Haase fought back after losing the first set against Argentina's Diego Schwartzman to win 4-6 6-3 6-3.
Kisner, Matsuyama share rain-delayed second-round lead
And also looking to become a first Italian-born victor of a Major is the long-time London-based Francesco Molinari . Hideki Matsuyama and Chris Stroud are lurking just one shot back.
Fourth-seeded Alexander Zverev of Germany rolled into the quarterfinals with a 6-4, 6-3 victory over 16th-seeded Nick Kyrgios of Australia, and Kevin Anderson of South Africa eliminated Sam Querrey of the United States 6-4, 6-1. I started to believe more and more again.
For nearly two decades, spectators have flocked to Federer's breathtaking matches and followed the ebb and flow of his career.
Federer is aiming for the third Rogers Cup win of his career and sixth title of a remarkable 2017 season.
Wimbledon champion Federer, who celebrated his 36th birthday on Tuesday, prevailed 4-6 6-4 6-2 in just under two hours in Montreal. I'm most happy that I'm actually really healthy going into the finals.
In another round-of-16 action, 18-year-old Canadian rising star Denis Shapovalov stunned world No. 2 Rafael Nadal 3-6, 6-4, 7-6 (7-4) and stymied the Spaniard's hopes of regaining the No.1 ranking this week.
"I saved four match points the first round (against Rogerio Dutra Silva)". I feel like I'm playing well, so I know that I have to serve a lot better tomorrow than I did today.
Federer will now prepare for a semifinal tilt against Robin Haase, who has needed three sets to beat his last two opponents in Montreal.