World number one Iga Swiatek beat Czech player Karolina Muchova at the Canadian Open after lengthy rain delays left the players waiting more than nine hours to complete the match.

Meanwhile, world number seven Coco Gauff cruised past Wimbledon champion Marketa Vondrousova 6-3 6-0.

American Gauff will face compatriot and doubles partner Jessica Pegula in the quarter-finals in Montreal.

Pegula swept past Italy's Jasmine Paolini 6-4 6-0 to secure her place in the last eight.

The American got the job done before the rain arrived, which disrupted play for most of the day and causing several matches to be postponed.

World number two Aryna Sabalenka's match against Liudmila Samsonova was moved to Friday, as well as the tie between Petra Kvitova and Belinda Bencic.

"For sure, it was a pretty extraordinary day," said Swiatek, who beat Muchova at Roland Garros in June to land her third title this year.

"I don't think I've had such a situation in my career so there is the opportunity to learn something new and see what I'm capable of. Even though we played this match, like, three times.

"You have to find energy, even though we've been here since 9am."

Swiatek saved several break points to take the opening set before Muchova frustrated the four-time Grand Slam champion when she levelled just before the rain halted proceedings.

On their return, Swiatek secured an early break before the rain reappeared and forced them off again. The break was most of the day, but Swiatek kept her concentration to prevail.

She will face American qualifier Danielle Collins, who beat Canadian Leylah Fernandez 6-2 6-3, in the next round.

World number three Elena Rybakina also advanced to the quarter-finals with a 6-3 6-3 victory over American Sloane Stephens and will now face Russian Daria Kasatkina, who beat the Czech Republic's Marie Bouzkova 6-3 6-4.