Serena Williams highlighted the first day of the Canadian Open, defeating Nuria Parrizas-Diaz 6-3 6-4 for her first win since the 2021 French Open.

In doing so, Williams became the fourth player since 2000 to win a WTA-level main draw match after turning 40, joining sister Venus Williams, as well as Kimiko Date Krumm and Martina Navratilova.

She also claimed the all-time record for wins at the Canadian Open, with 35, now one more than Chris Evert.

"I guess there’s just a light at the end of the tunnel," Williams said after the match. "I don’t know, I’m getting closer to the light. Lately that's been it for me. I can’t wait to get to that light."

She added: "I love playing though, so it’s like amazing. But I can’t do this forever. Sometimes you just want to try your best to enjoy the moments and do the best that you can."

Williams' older sister Venus, 42, was beaten on Monday by Swiss Jil Teichmann 6-2 6-3 with the match finshing after midnight following a delayed start due to rain.

One of the three seeded players in action on Monday, 15th seed Simona Halep had no issues cruising through the challenge of Donna Vekic 6-0 6-2.

It was similarly smooth sailing for 14th seed Karolina Pliskova in her all-Czech showdown against Barbora Krejcikova, winning 6-3 6-4, while Latvian 16th seed Jelena Ostapenko handled the challenge of Ukraine's Anhelina Kalinina 6-4 6-2.

Kazakhstan's Elena Rybakina defeated in-form qualifier Marie Bouzkova 7-5 6-7 (3-7) 6-1, likely earning a shot at Coco Gauff if the American wins as a heavy favourite tomorrow, while Brazil's Beatriz Haddad Maia beat Italy's Martina Trevisan 6-2 2-6 6-2 in a meeting of two top-30 players.

In a pair of all-American battles, Sloane Stephens edged Sofia Kenin 6-2 7-6 (7-5) 7-5, and world number 187 Asia Muhammad upset world number 25 Madison Keys in straight sets 7-6 (7-5) 6-4.

Alize Cornet defeated her French compatriot Caroline Garcia 3-6 6-3 6-3, and Canada's Katherine Sebov was unable to get the job done in front of her home fans, going down 6-3 2-6 5-7 to Yulia Putintseva.

In better news for the Canadians, Leylah Fernandez won 6-4 6-7 (2-7) 6-3 over Storm Sanders, while veteran two-time Wimbledon winner Petra Kvitova was beaten by Alison Riske 6-2 4-6 6-3.