The Canadians on tour had an undefeated Day 1 at the US Open, with 2019 champion Bianca Andreescu, 2021 finalist Leylah Fernandez and resurgent veteran Rebecca Marino picking up first-round wins.

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Andreescu, who defeated Serena Williams in the 2019 US Open final, overcame upset-minded Harmony Tan 6-0, 3-6, 6-1. Andreescu took 1 hour and 39 minutes to improve to 11-1 overall at the US Open.

"I think I started off very, very well, and then [Tan] kind of came back," Andreescu said. "She changed her game style. I felt like she was playing more aggressive, coming to the net.

"I was a bit thrown off guard, and then I had to regroup in the third set, because I know if I didn't, then I'm sure she could have won that third set. But I'm just happy with how I dealt with it at the end."

Wildcard Tan had already grabbed a famous first-round win at a major this year when she outlasted Serena Williams at Wimbledon. Tan backed that victory up by making it all the way to the Round of 16 in London.

But after being pushed into a third set by Tan on Monday, Andreescu rolled through the decider, where she won 13 of her 14 first-service points and converted both of her break points.

Andreescu will now face in-form No.15 seed Beatriz Haddad Maia of Brazil in the second round. Haddad Maia, who has won two WTA 250 titles this season and reached the WTA 1000 final in Toronto earlier this month, cruised past Ana Konjuh 6-0, 6-0 on Monday.

"[Haddad Maia is] playing really, really well," Andreescu said. "I know I played her but it was back in 2016. ... It wasn't an easy match, and I'm sure Wednesday definitely won't be an easy match, as well.

"She's playing really well. But I'm also playing really well, so I think it's going to be a great matchup."

Marino joined Andreescu in the second round with a quick 6-2, 6-3 win over Poland's Magdalena Frech. Marino continues her solid hard court summer, where she reached her first WTA quarterfinals since 2018 in both Washington and Granby.

World No.106 Marino, who has made a comeback after four years off tour between 2014 and 2017, had 19 winners to Frech's 10. The 31-year-old Marino is now into the US Open second round for the first time since her tournament main-draw debut back in 2010.

Marino will now take on Daria Snigur in the second round. Ukrainian qualifier Snigur pulled off a massive shocker on Monday by toppling Simona Halep in the first round.

In the last match of the day, No.14 seed Fernandez kicked off her 2022 campaign with a 6-3, 6-4 win over France's Oceane Dodin. Last year's runner-up to Emma Raducanu needed just an hour and 12 minutes to clinch her victory at 11:30 p.m. on Louis Armstrong Stadium.

To polish off the undefeated day for Canada, Fernandez fired 26 winners in her first meeting with Dodin, while giving up just nine unforced errors.

Fernandez will now have to face one of the hottest players of the summer when she takes on big-serving Liudmila Samsonova in the second round. Samsonova, who won titles in Washington and Cleveland this month alone, beat 16-year-old Czech qualifier Sara Bejlek 6-3, 6-1.