Earlier, four-time Grand Slam champion Naomi Osaka registered a dominant 6-2 6-4 win over 22nd seed Jelena Ostapenko.

"Granted, she broke me a couple times, but she's a really good returner, so I can't take that personally," said Osaka.

Japan's Osaka, a winner twice at the US and Australian Opens, will play Anastasia Sevastova after the 35-year-old upset defending champion and third seed Jessica Pegula 3-6 6-4 6-1.

American Pegula was on an 11-match winning run in Montreal but an a error-strewn deciding set cost her against world number 386 Sevastova.

Latvia's Sevastova, like Osaka, returned from maternity leave in early 2024 and has now registered her first win over a top-five opponent since 2017.

"It was a weird match for me," said Pegula. "I felt like I had total control and then I just played a couple of terrible games for, like three games.

"That totally flipped the momentum of the match, and I went from being up a set and 2-0 to being down very quickly.

"I don't really feel like I'm playing great tennis. At times I am, but I feel very up and down, kind of sloppy, which I don't like. I've got to figure it out."