Angelique Kerber and Simona Halep had contrasting wins as the seeded pair set up a semi-final showdown at the Rogers Cup.
German second seed Kerber eased past teenager Daria Kasatkina 6-2 6-2 in Montreal on Friday.
Last year's runner-up Halep - the fifth-seeded Romanian - had a tougher time against fellow seed Svetlana Kuznetsova, rallying to win the quarter-final clash 3-6 6-1 6-1.
Madison Keys won through to her first Rogers Cup semi thanks to a 7-6 (7-3) 1-6 6-0 win over fellow seed Anastasia Pavlyuchenkova, while Kristina Kucova's fairytale run continued against Johanna Konta in straight sets.
KERBER BACK TO HER BEST
Kerber flirted with elimination on Thursday but she had no such trouble against unseeded Russian Kasatkina.
After rallying to beat 17th seed Elina Svitolina in three sets in the last 16, Australian Open champion Kerber eased past her 19-year-old opponent in an hour.
Despite a hiccup to open the match, Kerber dropping serve in the first game, the Wimbledon runner-up soon found her groove as she swept aside Kasatkina to reach the semis.
Her semi-final opponent Halep, meanwhile, was forced to dig deep against ninth-seeded Russian Kuznetsova.
Halep was completely outplayed in the opening set, but she produced a stirring comeback to see off the two-time grand-slam champion in blistering conditions in Canada, taking a 3-0 lead in the second set after Kuznetsova double faulted.
The Romanian never looked back, staying ahead as she moved a step closer to another Montreal final.
HIGH-FLYING KONTA FALLS SHORT
Friday promised so much but it ended in disappointment for the in-form Konta, who was stunned 6-4 6-3 by Kucova.
Flying high after beating seven-time grand-slam champion Venus Williams to win her first WTA Tour title in California last week, Konta was barely given a sniff against Kucova in her bid to crack the top 10.
Konta fended off a match point on serve in the eighth game but she was unable to deny Kucova a spot in the semis.
GOOD NIGHT FOR KUCOVA IN MONTREAL
World number 121 Kucova reached her second WTA semi-final after eclipsing Konta on Friday, adding the Brit to her list of scalps, which include Yanina Wickmayer, Carla Suarez Navarro and Eugenie Bouchard.
Kerber's serve was on song against Kasatkina, with the 28-year-old winning 73 per cent of her first serves, compared to just 35 per cent from her opponent.
Konta was left to rue her wastefulness, only converting one of five break-point opportunities in her straight-sets loss to Kucova.
HALEP RELIEVED TO WIN AS KERBER AWAITS
After seeing off Kuznetsova, Halep said: "It was very tough, I feel really tired now, she played very well and she's very strong so I knew it was going to be like this. All I can say is that I'm very happy I could win against her, because we always have tough matches.
"I was a little bit nervous at the beginning of the match and I didn't really feel the ball. But I just tried to be aggressive and play my game. I was doing everything, I was fighting today."
Of the upcoming match, Kerber added: "It's going to be tough. We've played a lot of good matches in the past. I'm sure the crowd will support both of us so I'm really looking forward to playing her tomorrow."
BLOCKBUSTER HEADLINES SEMI-FINALS
A spot in the Rogers Cup final is up for grabs as Kerber and Halep - who boasts a 3-2 record - go head-to-head on Saturday afternoon. In the evening, Kucova faces Keys in the other semi-final.