Top-ranked Iga Swiatek outlasts Muchova in Montreal

Coming off her fourth victory of the year last week at home in Warsaw, Swiatek finished off Muchova after they were delayed for three hours following the second set and again for nearly another three hours early in the third.

Swiatek also beat Muchova in June in the French Open final. The 22-year-old player leads the tour with 49 match victories this year.

Swiatek set up a last-eight match against the winner of a late match between hometown favourite Leylah Fernandez and American Danielle Collins.

In the only match completed in the afternoon, fourth-seeded Jessica Pegula of the United States beat Italy's Jasmine Paolini 6-4 6-0.

Pegula will face the winner of a match between sixth-seed Coco Gauff of the United States and ninth-seeded Marketa Vondrousova of the Czech Republic. Vondrousova won at Wimbledon.

No.10 Daria Kasatkina of Russia topped Czech Marie Bouzkova 6-3 6-4. Kasatkina will play the winner of a match between No.3 Elena Rybakyna and Sloane Stephens.

The match between No.2 Aryna Sabalenka and No.15 Liudmila Samsonova was pushed back to Friday.