GUADALAJARA, Mexico -- Teenager Marina Stakusic fought off four match points to claim the biggest win in her career after defeating top-seeded Jelena Ostapenko 6-3, 5-7, 7-6 (0) on Thursday to advance to the Guadalajara Open quarterfinals.
The 19-year-old Canadian trailed 4-0 in the third set and fought off the four match points when she was down 5-3.
"I'm happy to pull through, it was a roller coaster, I got a chance to close it in the second and I didn't, but I'm happy with the win and excited with the quarters," said Stakusic, who got into the main draw on a wild card.
Stakusic defeated Olympic semifinalist Anna Karolina Schmiedlova 6-2, 6-4 in the opening round and then Ostapenko for her first-career win over a top-20 player. Last year she lost to Barbora Krejcikova in the Billie Jean King Cup Finals.
The Canadian, ranked 155th, is the first wild-card entry to reach the quarterfinals in Guadalajara. Stakusic will next play fifth-seeded Magdalena Frech, who beat Ashley Krueger 3-6, 6-3, 6-1 in the last match of the night.
Ostapenko, who is ranked 12th and won the 2017 French Open, had 17 double faults in the match.
Earlier, fourth-seeded Caroline Garcia held off Ena Shibahara 7-6 (3), 7-6 (5) and also advanced to the quarterfinals, where she will meet Marie Bouzkova, who in the first match of the day breezed past qualifier Lucrezia Stefanini 6-2, 6-1.
The 30-year-old Garcia will be playing in her first quarterfinal since she advanced to the Rouen semifinals last April.
"We played very different styles, she is a player that does not suit me, I need to play solid, and I will see what I can do differently to beat her," said Garcia, who is 0-4 against Bouzkova.
The tournament is being played on hard courts at the Complejo Panamericano de Tenis in Guadalajara.