Daniil Medvedev and Stefanos Tsitsipas moved one step closer to a final showdown at the National Bank Open with quarterfinal victories Friday night.
The pair of top-three seeds will take on unseeded Americans in their semifinal matches before a potential clash in Toronto.
Meanwhile in Montreal, Aryna Sabalenka and Karolina Pliskova set up semifinals featuring two top-four seeds with their Friday victories.
There are two top-four seeds and a pair of unseeded players remaining in both the men's and women's singles draws. All four matches will be played Saturday.
No. 1 Daniil Medvedev def. No. 7 Hubert Hurkacz, 2-6, 7-6 (8-6), 7-6 (7-5)
No. 3 Stefanos Tsitsipas def. No. 6 Casper Ruud, 6-1, 6-4
Reilly Opelka def. No. 10 Roberto Batista Agut, 6-3, 7-6 (7-1)
John Isner def. No. 11 Gael Monfils, 7-6 (7-5), 6-4
Medvedev picked up his second win in as many months over Hubert Hurkacz to move on to the semifinal round.
The top-seed had to go the distance again to eliminate the Pole, who took him to five sets in the Wimbledon round of 16.
Unlike their five-setter in London, Medvedev lost the first set. He needed multiple tiebreak victories to put away the seventh-seeded player.
Medvedev used three sets to get past two of his three opponents in Toronto. He also fell in the first set to Alexander Bublik in his opening match.
Tsitsipas had a much easier time on the court in Ontario, breezing past Casper Ruud in the other matchup of seeded players.
The third-seeded Greek appears to be on a collision course with Medvedev to play in the championship match.
Two years ago, Medvedev reached the final, but he only won three games over two sets in a defeat versus Rafael Nadal.
Reilly Opelka and John Isner will attempt to play spoiler to the high-profile final.
Opelka won his second match against a seeded player in Toronto by taking down Roberto Bautista Agut in straight sets. The American eliminated No. 14 seed Grigor Dimitrov in the second round.
Isner used a straight-set win over Gael Monfils to finish off the four-match schedule in Toronto.
The American dealt with the challenges posed by the Frenchman, who produced a handful of exciting winners under the lights.
To reach the final, Isner needs to upset Medvedev. Opelka, meanwhile, must find a way past the in-form Tsitsipas.
No. 1 Aryna Sabalenka def. No. 8 Victoria Azarenka, 6-2, 6-4
No. 4 Karolina Pliskova def. Sara Sorribes Tormo, 6-4, 6-0
Jessica Pegula def. No. 13 Ons Jabeur, 1-6, 7-6 (6-4), 6-0
Camila Giorgi def. No. 15 Coco Gauff, 6-4, 7-6 (7-2)
The two sides of the women's singles bracket could not look more different.
Top seed Aryna Sabalenka and No. 4 seed Karolina Pliskova set up a head-to-head battle in the final four through straight-sets quarterfinal wins in Montreal.
Pliskova had the easier time on court with her opponent. She blanked Sara Sorribes Tormo in the second set.
Sabalenka conceded six games in the showcase match of the round against eighth-seeded Victoria Azarenka. That matchup was just the third of the tournament between seeded foes.
The bottom half of the bracket produced a pair of unseeded semifinalists who advanced in contrasting manners.
American Jessica Pegula won a single game in the first set against Ons Jabeur but rallied back to win the match in the third set.
Pegula eked out a second-set tiebreak victory and then slammed the door on the No. 13 seed with a shutout in the third set.
Coco Gauff, the other American left in the draw, dropped a straight-sets result to Camila Giorgi. The Italian finished off the contest with a five-point advantage in a second-set tiebreak.
The Pegula-Giorgi semifinal marks the second time in the past two editions of the tournament that one women's singles final four match features two unseeded players.