MONTREAL — Clara Tauson of Denmark upset second-seeded Wimbledon champion Iga Swiatek of Poland 7-6 (1), 6-3 on Sunday night to reach the National Bank Open quarterfinals.

The 6-foot Tauson, seeded 16th in the hard-court event that ends Thursday, avenged a loss to Swiatek at Wimbledon to set up a match Tuesday with sixth-seeded Australian Open winner Madison Keys of the United States.

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“I think, obviously, getting a win against her after losing to her in Wimbledon a couple of weeks ago is, obviously, nice, because I was not feeling great in that match, and I felt like I was playing some good tennis in Wimbledon,” Tauson said. “So I felt like if I could keep that going, I thought I had a shot.”

Tauson won her lone tour title in New Zealand in January, beating fellow Montreal quarterfinalist Naomi Osaka of Japan in the final.

Keys outlasted 11th-seeded Karolina Muchova of Czechia 4-6, 6-3, 7-5 in the windy afternoon session.

“Clara’s a fantastic ball-striker,” Keys said about the quarterfinal match. “She’s got a big serve. She’s got a lot of power on both sides. She covers the court quite well on top of everything, so I feel like she’s one of those matches where you kind of have to temper a little bit and not go for things too quickly.”

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Osaka also advanced in the afternoon, routing Anastasija Sevastova of Latvia 6-1, 6-0 in 49 minutes — the second-fastest victory of her career. Osaka had a 42-minute victory in a 2016 event in Brazil.

Osaka reached the final eight of a WTA 1000 or Grand Slam event for the first time in 19 months. On Tuesday, she will face 10th-seeded Elina Svitolina of Ukraine, a 6-4, 6-1 winner over fifth-seed Amanda Anisimova of the United States.

On Monday night in the quarterfinals, 18-year-old Canadian Victoria Mboko will face Jessica Bouzas Maneiro of Spain, and Marta Kostyuk of Ukraine will meet ninth-seeded Elena Rybakina of Kazakhstan.