Leading Briton Katie Boulter advanced to the second round of the Canadian Open but fellow countrywoman Harriet Dart was eliminated.
Boulter won 6-4 3-6 6-1 against American Bernarda Pera, who is ranked 80 in the world, at Sobeys Stadium in Toronto.
She will play Brazilian world no. 22 Beatriz Haddad Maia on Thursday. In March, she defeated Maia when winning the San Diego Open.
Three-ranked Briton Dart lost against world-ranked Russian Diana Shnaider 3-6 6-3 6-7 (2-7).
Dart earned a place in the main draw as a lucky loser, having been taken off in a wheelchair when she retired with cramp in qualifying on Monday.
Shnaider will play Poland’s Magdalena Frech in the second round.
American former world number one Naomi Osaka beat Tunisia’s ninth seed Ons Jabeur 6-3 6-1, her fifth victory over a top-20 opponent this year following her return from maternity leave.