TOKYO -- The punishing heat and humidity didn't bother Leylah Fernandez on Saturday. There were no first-time Olympic jitters either.

The 18-year-old left-hander from Montreal showed the mettle she's known for in a first-round battle at the Tokyo Games, topping Ukraine's Dayana Yastremska 6-3, 3-6, 6-0 on a mixed day for Canadian players at the Ariake Tennis Park.

"I'm very happy with myself," Fernandez said. "I was able to fight through the heat and fight through my opponent."

The bright sunshine and 34 C temperature for the late morning start made the outdoor hardcourts hot and quick. The conditions suited the Canadian teenager's game nicely as she used powerful ground strokes to wear down her opponent in the opening set.

Yastremska, the world No. 46, also hits a big ball with consistent pace. She rebounded in the second set before the 72nd-ranked Fernandez put things away with a dominant decider, taking the match in two hours five minutes.

"She doesn't have much pressure and has nothing to lose," said Canadian women's coach Heidi el Tabakh. "She's very happy to be here. She's a fighter and she believes that she can make it and she can beat these top girls.

"She definitely belongs and she proved today that she does."

Fernandez will next play eighth-seeded Barbora Krejcikova, who advanced when Kazakhstan's Zarina Diyas retired while down 5-2.

In women's doubles play, the seventh-seeded duo of Gabriela Dabrowski of Ottawa and Sharon Fichman of Toronto dropped a 7-6 (3), 6-4 decision to Brazil's Laura Pigossi and Luisa Stefani.

The Canadians fought off three set points to force a tiebreaker in the opener, but some unforced errors proved costly.

"They were able to string more points together better than we did," Dabrowski said. "So I feel like that honestly was the main difference."

It was one and done for Fichman, who has been nursing a right shoulder injury of late. Dabrowski, meanwhile, will turn her attention to teaming with Felix Auger-Aliassime in the mixed doubles draw.

Dabrowski, a two-time Grand Slam mixed doubles champion, has had two training sessions this week with the 20-year-old Montrealer, who will make his career debut in the discipline.

"When you team up for the first time, sometimes it works because (opponents) don't know you and you have the surprise factor," Dabrowski said. "Hopefully it's like that here."

Auger-Aliassime, the world No. 15 in men's singles, was scheduled to open against Britain's Andy Murray on Sunday. The Canadian won his first career ATP doubles title last fall when he teamed with Poland's Hubert Hurkacz to win the Paris Masters.

Auger-Aliassime has worked in some mixed doubles training with Dabrowski in recent days. They practised with a Dutch duo and also hit with el Tabakh and men's coach Frank Dancevic.

"It's going to be interesting, she has a few things to show me," Auger-Aliassime said. "She has experience down that path, winning Grand Slams in mixed doubles ... I'm going to try to do my best.

"I think we can be a good team that can be a contender for a medal."

Unlike regular tournaments, where championship finals serve as the carrot, there are three Olympic medals on the line in each discipline at the Games. Mixed doubles also offers a taut 16-team draw while 32 teams play down in men's and women's doubles events.

"So you win two matches and you're already a medal contender," Dancevic said of the mixed format.

 Mixed doubles was scheduled to begin Wednesday, a day after the draw was to be finalized. Auger-Aliassime and Dabrowski would be the lone Canadian entry.

"They're both great players and I think they can really (do) some damage here," said el Tabakh.

There was little relief from the scorching sunshine on the side courts where the Canadians played Saturday. Blinding rays made serving difficult from the north end of the playing surface.

Umbrellas over the court benches offered the only shade. Court crew members did their part by holding portable air conditioner hoses close to the players' heads at changeovers.

-- this report by The Canadian Press was first published July 24, 2021.