Qualifier Veronika Kudermetova upset second-seeded Karolina Pliskova 4-6, 6-4, 6-3 to advance to the quarterfinals of the Ostrava Open on Thursday.

The Russian will face American Jennifer Brady, who eliminated qualifier Daria Kasatkina 7-5, 6-2.

More Images
Cori Gauff of U.S. returns a ball against Aryna Sabalenka of Belarus during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Qualifier Veronika Kudermetova upset second-seeded Karolina Pliskova 4-6, 6-4, 6-3 to advance to the quarterfinals of the Ostrava Open on Thursday.

Karolina Pliskova of Czech Republic plays a ball against Veronika Kudermetova during the J&T Banka Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

The 16-year-old Gauff beat Sabalenka in Lexington in August en route to the semifinals and held a 5-2 lead in the third set before Belarusian came back.

Veronika Kudermetova of Russia returns a ball against Karolina Pliskova of Czech Republic during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

“She’s 16 and she’s playing on this level," Sabalenka said. "I would like to be on this level when I was 16.”

Karolina Pliskova of Czech Republic returns a ball against Veronika Kudermetova during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

More AP Tennis coverage: https://www.apnews.com/apf-Tennis and https://twitter.com/AP_Sports

Veronika Kudermetova of Russia returns a ball against Karolina Pliskova of Czech Republic during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Veronika Kudermetova of Russia returns a ball against Karolina Pliskova of Czech Republic during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Third-seeded Aryna Sabalenka came from two breaks down in the deciding set to eliminate American teenager Coco Gauff 1-6, 7-5, 7-6 (2).

Cori Gauff of U.S. returns a ball against Aryna Sabalenka of Belarus during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Cori Gauff of U.S. returns a ball against Aryna Sabalenka of Belarus during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

The 16-year-old Gauff beat Sabalenka in Lexington in August en route to the semifinals and held a 5-2 lead in the third set before Belarusian came back.

“I just need to play a little bit smarter on pressure points, to make my opponent play,” Gauff said.

Sabalenka credited Gauff with her forcing her to play long rallies.

Karolina Pliskova of Czech Republic plays a ball against Veronika Kudermetova during the J&T Banka Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Karolina Pliskova of Czech Republic plays a ball against Veronika Kudermetova during the J&T Banka Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

“She’s 16 and she’s playing on this level," Sabalenka said. "I would like to be on this level when I was 16.”

Also, seventh-seeded Elise Mertens beat Karolina Muchova 6-4, 6-2 while Ons Jabeur defeated former French Open champion Jelana Ostapenko 6-4, 6-4.

The hard-court indoor event was added to the tour after tournaments in China were canceled due to the coronavirus pandemic.

Veronika Kudermetova of Russia returns a ball against Karolina Pliskova of Czech Republic during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Veronika Kudermetova of Russia returns a ball against Karolina Pliskova of Czech Republic during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

More AP Tennis coverage: https://www.apnews.com/apf-Tennis and https://twitter.com/AP_Sports

Karolina Pliskova of Czech Republic returns a ball against Veronika Kudermetova during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Karolina Pliskova of Czech Republic returns a ball against Veronika Kudermetova during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Veronika Kudermetova of Russia returns a ball against Karolina Pliskova of Czech Republic during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)

Veronika Kudermetova of Russia returns a ball against Karolina Pliskova of Czech Republic during the Ostrava Open 2020 tennis tournament in Ostrava, Czech Republic, Thursday, Oct. 22, 2020. (Jaroslav OzanaCTK via AP)