Aryna Sabalenka threw a ball away in frustration.

The No. 3 player in women's tennis then slammed her racket to the court as emotions boiled over.

Sabalenka was down a set to an opponent she had struggled against in the past.

Things only got worse.

The Belarusian star was stunned 6-4, 6-2 by Amanda Anisimova of the U.S. in Saturday's National Bank Open quarterfinals at a windswept Sobeys Stadium.

Sabalenka, who did not speak with reporters after the match, lost to the WTA Tour's 132nd-ranked player for a fifth time in seven meetings.

"Always ends up being a very good match between us," Anisimova said. "If I'm not 100 per cent there, I'm not likely to win against a player like that."

Watch the National Bank Open on Sportsnet

The top stars of the tennis world return to Toronto and Montreal for the National Bank Open. Catch the tournaments live all week long on Sportsnet and Sportsnet+.

Broadcast Schedule

She broke the tournament's No. 2 seed up 5-4 in the first set when Sabalenka — the two-time defending Australian Open champion — fired long and took out some anger on her racket with flags fluttering in the breeze above the grandstand.

"It was really tough," Anisimova said of the blustery conditions. "Took some time for me to get used to that."

The American broke again for a 4-2 lead in the second set before serving out to take a 5-2 advantage on the campus of York University.

Sabalenka, who missed Wimbledon with a shoulder injury and skipped the Paris Olympics, committed her eighth double fault of the match down love-40 to seal Anisimova's first trip to a WTA 1000 semifinal.

"Feels amazing," she said. "I've been working really hard the last few months."

Anisimova will face Emma Navarro — also into her first WTA 1000 semifinal — on Sunday after the No. 8 seed downed U.S. counterpart Taylor Townsend 6-3, 7-6 (5).

"Playing some great tennis," Anisimova said of Navarro. "I'm sure it will be a tough match."

Defending champion and No. 3 seed Jessica Pegula defeated Peyton Stearns 6-4, 7-5 in another all-American quarterfinal to also advance.

[brightcove videoID=6360252503112 playerID=JCdte3tMv height=360 width=640]

"Really tough conditions, a lot of wind, a lot of gusting," said the tour's sixth-ranked player. "I just reminded myself of what I needed to focus on."

Pegula will face No. 14 Diana Shnaider, who knocked off top seed Coco Gauff of the U.S. on Friday, after she got past fellow Russian and No. 6 Liudmila Samsonova 4-6, 6-1, 6-4 in the US$3.2-million event that saw plenty of withdrawals — including the top-ranked Iga Swiatek — before the bracket was set last weekend.

[brightcove videoID=6360248907112 playerID=JCdte3tMv height=360 width=640]

The five U.S.-born women in the final eight are the most at a WTA 1000 event since the format's inception in 2009, and the most at any tour stop since 2001.

"I feel like we've been strong for the last few years," said Pegula, who represented the U.S. at the Olympics. "It's amazing we have five girls in the top-15, which is a crazy stat. Hopefully one of us can step up and win some bigger tournaments."

All of Canada's singles entries were eliminated earlier in the week — both here in Toronto and at the men's event in Montreal — but the women's doubles field still had plenty of red Maple Leafs dotting the page entering Saturday.

Leylah Fernandez of Laval, Que., and younger sister Bianca beat France's Kristina Mladenovic and China's Zhang Shuai 5-7, 7-5 (12-10) in the quarters to guarantee a least one Canadian in Monday's final.

"We fought through from the first point all the way to the last," said Leylah Fernandez, who was seething after getting knocked out of singles Thursday. "I'm just happy that I was able to play doubles with my sister. We're in the semifinals together."

The siblings will face the top-seeded duo of Ottawa's Gabriela Dabrowski and New Zealand's Erin Routliffe after they came back to beat wild-card entry Ariana Arseneault of Richmond Hill, Ont., and Edmonton's Mia Kupres 3-6, 6-3 (10-4).

"We've been sticking together in the tough moments," said Dabrowski, who won Olympic bronze in mixed doubles for Canada in Paris alongside Montreal's Felix Auger-Aliassime.

The finals at this year's NBO tournament are being played Monday instead of the traditional Sunday slot because of scheduling related to the Paris Games.

Townsend's unlikely run as a "lucky loser" — the first to ever make a WTA 1000 quarterfinal — at Canada's tennis championship came to an end on Centre Court after entering the draw as an injury replacement.

"This week has been amazing," she said. "It's not anything shy of what I believe that I could do."

Anisimov, meanwhile, will have a chance to climb another rung in her journey after stepping away from tennis last season.

"Gained a different perspective," said the former world No. 21. "I'm just really happy to be back."

Sabalenka latest to be upset at National Bank Open

NHL Newsletter

Blue Jays Newsletter

Raptors Newsletter

Informative

Service Plus

Marketing

Sponsored

Contest

Event

Affiliate