Collins was coming off a first-round defeat at the US Open to countrywoman Caroline Dolehide.
The 30-year-old, who is playing her final season after announcing her retirement plans at January’s Australian Open, missed a valuable opportunity to move up the leaderboard in the race to the WTA Finals. Collins currently sits in eighth, though is on the outside looking in as Barbora Krejcikova—ranked two places behind—earns an automatic spot as a 2024 Grand Slam champion to the eight-competitor field if she finishes inside the Top 20.
Camila Osorio pulled off a tremendous comeback to also oust a seed. Down 0-5 in a deciding set, the Colombian stormed back to deny seventh-seeded Veronika Kudermetova, 7-6 (5), 6-7 (2), 7-5, in three hours and 21 minutes.
Kamilla Rakhimova awaits next. The 23-year-old led Victoria Azarenka, 6-2, 3-0, before the No. 3 seed retired from their encounter with a shoulder injury.
