GUADALAJARA, Mexico — Second-seeded Danielle Collins lost in the second round of the Guadalajara Open on Wednesday and third seed Victoria Azarenka withdrew from her match because of injury.

Qualifier Olivia Gadecki, ranked No. 152, pulled off a major upset with a 6-3, 6-3 win over Collins to reach the quarterfinals of an elite WTA tournament for the first time. She beat former US Open champion Sloane Stephens in the first round.

The 30-year-old Collins, who is retiring at the end of the season, arrived at Guadalajara with 39 tour-level wins and two titles on tour this year and is currently ranked 11th.

Earlier, Kamilla Rakhimova advanced to the quarterfinals after two-time major winner and former No. 1-ranked Victoria Azarenka withdrew from their match in the second set while trailing 6-2, 3-0.

Rakhimova will next play Camila Osorio, who beat seventh-seeded Veronika Kudermetova 7-6, 6-7 (2), 7-5.

The tournament is played in hard-court at the Complejo Panamericano de Tenis, in Guadalajara.