Karolina Pliskova of Czech Republic hits a return during the women's singles third round match against Ons Jabeur of Tunisia at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020. (Photos: Xinhua)

Ons Jabeur of Tunisia hits a return during the women's singles third round match against Karolina Pliskova of Czech Republic at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Ons Jabeur of Tunisia hits a return during the women's singles third round match against Karolina Pliskova of Czech Republic at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Karolina Pliskova of Czech Republic hits a return during the women's singles third round match against Ons Jabeur of Tunisia at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Garbine Muguruza of Spain hits a return during the women's singles third round match against Dayana Yastremska of Ukraine at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Karolina Pliskova of Czech Republic serves during the women's singles third round match against Ons Jabeur of Tunisia at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Belinda Bencic of Switzerland hits a return during the women's singles third round match against Yulia Putintseva of Kazakhstan at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Belinda Bencic of Switzerland serves during the women's singles third round match against Yulia Putintseva of Kazakhstan at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Yulia Putintseva of Kazakhstan hits a return during the women's singles third round match against Belinda Bencic of Switzerland at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Yulia Putintseva of Kazakhstan hits a return during the women's singles third round match against Belinda Bencic of Switzerland at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Petra Kvitova of the Czech Republic hits a return during the women's singles third round match against Jelena Ostapenko of Latvia at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Belinda Bencic of Switzerland hits a return during the women's singles third round match against Yulia Putintseva of Kazakhstan at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Jelena Ostapenko of Latvia hits a return during the women's singles third round match against Petra Kvitova of the Czech Republic at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Belinda Bencic of Switzerland hits a return during the women's singles third round match against Yulia Putintseva of Kazakhstan at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Petra Kvitova of the Czech Republic celebrates after winning the women's singles third round match against Jelena Ostapenko of Latvia at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020. (Photo by Nikku/Xinhua)

Jelena Ostapenko of Latvia hits a return during the women's singles third round match against Petra Kvitova of the Czech Republic at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Petra Kvitova of the Czech Republic hits a return during the women's singles third round match against Jelena Ostapenko of Latvia at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Zheng Saisai of China hits a return during the women's singles third round match against Kiki Bertens of the Netherlands at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Zheng Saisai of China hits a return during the women's singles third round match against Kiki Bertens of the Netherlands at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Zheng Saisai of China hits a return during the women's singles third round match against Kiki Bertens of the Netherlands at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.

Zheng Saisai of China serves during the women's singles third round match against Kiki Bertens of the Netherlands at the 2020 WTA Qatar Open in Doha, Qatar, Feb. 26, 2020.