Ajla Tomljanovic has battled to a three-set victory over home favourite Saisai Zhang at the Zhengzhou Open to set up a testing semi-final clash with world No.2 Karolina Pliskova.

Australian No.2 Tomljanovic, who claimed the biggest win of her season with a straight-sets victory over world No.8 Kiki Bertens in the previous round in China, ensured her passage to the last four on Friday with a 6-1 6-7 (7-4) 6-4 over Zhang, ranked eight places above her at 38.

She now faces top seed Pliskova, who started Friday in the last-16 and ended the day in the semis after defeating Polona Hercog and Sofia Kenin in succession.

Pliskova’s match against Slovenian Hercog was suspended on Wednesday due to rain with the score at 6-3 2-5 and she only returned to court two days later after rain washed out Thursday’s matches.

The Czech claimed five games in a row to see off Hercog 6-3 7-5 and carried that form into her quarter-final clash with sixth-seeded American Kenin, winning 6-4 4-6 6-1.

“To play two matches in a day, it’s never easy,” said the Czech, who saved nine break points, including six in the final set.

“I also played Tomljanovic in Rome, and in Brisbane on hard courts, so I know her game quite well, I could say,” Pliskova said.

“She’s dangerous and beat Kiki Bertens, so she’s playing well. I didn’t see much of her tennis here but it’s the semifinals, so everyone is confident and playing their best tennis.”

The upset of the day saw France’s unseeded Kristina Mladenovic beat second seed and new world No.3 Elina Svitolina 6-4 4-6 6-3 in the final match of the day that lasted two hours and 45 minutes.

Mladenovic will now face Croatia’s Petra Martic, who earlier beat fourth seed Aryna Sabalenka 7-5 5-7 6-4 in another lengthy encounter that lasted two hours and 39 minutes.