World number one Iga Swiatek qualified for the semi-finals of the Canadian Open, defeating American Danielle Collins in three sets.

The 22-year-old Pole won 6-3 4-6 6-2 in Montreal to set up a semi-final match with world number three Jessica Pegula.

Swiatek capitalized on Collins’ second serve in the decider, breaking twice to win her 50th match of the season.

Earlier, Pegula beat compatriot and doubles partner Coco Gauff 6-2, 5-7, 7-5.

“I really wanted to play hard and I’m very happy that I was able to go strong in the third set,” said four-time Grand Slam champion Swiatek. “Sure, I’ve been looking for that. Today I felt like I really needed to go a little higher in intensity.”

Pegula, 29, broke her 19-year-old opponent twice en route to claiming the first set, but Gauff took the lead in the second.

Gauff was unhelpful to nine double faults and Pegula took a decisive break at 5-5 in the third set before serving out for the match.

“It’s always difficult to play your marital partner,” Pegula said.

“It just got down to the wire and who would have competed better.”

Lyudmila Samsonova defeated world number two Aryna Sabalenka 7-6 (7-2), 4-6, 6-3 in the postponed third-round match.

Russian Samsonova will play Belinda Bencic in the quarter-finals after the Swiss came back from a set down to win 6-7 (3-7), 6-3, 6-1 over Petra Kvitova in another match that had to be moved to Friday. .