Top-seeded Caroline Wozniacki of Denmark advanced to the semifinals of the Istanbul Cup on Friday after being taken to three sets by eighth-seeded Karolina Pliskova of the Czech Republic.
Wozniacki, who served six aces and saved four of five break points, won 6-1, 3-6, 6-2.
She was joined by second-seeded Roberta Vinci of Italy who beat sixth-seeded Kurumi Nara of Japan 6-0, 6-2.
Vinci next plays Croatian qualifier Ana Konjuh who, in her first WTA quarterfinal, defeated fourth-seeded Elina Svitolina of Ukraine 6-4, 1-6, 6-1.
Kristina Mladenovic of France ousted Francesca Schiavone of Italy 3-6, 6-3, 7-5 to set up a semifinal against Wozniacki.