PRAGUE — Second-seeded Petra Kvitova advanced to the Prague Open semifinals after dominating fellow Czech Katerina Siniakova 6-3, 6-3 on Thursday.

On the way to her third straight-sets victory, Kvitova hit 21 winners at her debut in the tournament.

She next faces sixth-seeded Zhang Shuai of China who defeated Jasmine Paolini of Italy 6-4, 6-3.

Kvitova and Zhang have a 2-2 record against each other.

Seventh-seeded Mihaela Buzarnescu of Romania reached her second semifinal this year by beating Kristyna Pliskova of the Czech Republic 6-2, 6-3.

She will meet Italian Camila Giorgi, who knocked out former U.S. Open champion Samantha Stosur 6-2, 6-3.