Top seed Karolina Pliskova eased herself into the quarter-finals of the Tianjin Open on Wednesday with a 6-1 6-2 victory over Polona Hercog.

The Czech, who won her second title of the year in Tokyo last month, was in control throughout and won the first five games of the match.

The second set was slightly tougher for Pliskova, who saved a break point with a drop volley and then sent down an ace to bring up a fourth match point. Another big serve forced a Hercog error to seal the win.

Pliskova won 80 per cent of her first serve points and faced just one break point against her serve, which came in the very last game of the match.

Aryna Sabalenka was also a comfortable winner as she saw off Magda Linette 6-1 6-3 in one hour and 13 minutes.

At the WTA Ladies Linz in Austria, German wildcard Andrea Petkovic pulled off a shock when she defeated top seed Julia Goerges in their first-round clash.

Petkovic beat compatriot Goerges, the world number nine, 1-6 7-5 6-4 after two hours.

Earlier, number three seed Barbora Zahlavova Strycova came through her first-round match against Belgium’s Kirsten Flipkens with a 7-6 (4) 7-6 (5) win.

Anastasia Pavlyuchenkova, the sixth seed from Russia, had to come from behind to beat Vera Lapko of Belarus 5-7 7-6 (4) 6-3.

Ninth seed Katerina Siniakova, though, lost 7-5 6-0 to Russian Ekaterina Alexandrova and Belgian Alison Van Uytvanck recovered to beat Anna Karolina Schmiedlova in three sets, 1-6 7-6 (3) 7-6 (5).

In Wednesday’s other later matches, Dutch world number 10 Kiki Bertens, the second seed, defeated home player Barbara Haas 6-2 6-1 before Italian Camila Giorgi beat Swiss Jil Teichmann in straight sets, 7-6 (2) 6-3.

At the Prudential Hong Kong Tennis Open, fourth seed Garbine Muguruza secured her place in the quarter-finals with a 6-2 6-1 win over Romanian Ana Bogdan.

Number eight seed Alize Cornet, however, is out after the Frenchwoman was beaten in three sets, losing 6-4 4-6 7-6 (5) to Thailand’s Luksika Kumkhum, ranked 105 in the world.

Teenager Dayana Yastremska is through after the 18-year-old’s earlier 6-3 6-3 success against Zheng Saisai of China, while Slovakia’s Kristina Kucova coasted past Bulgarian Viktoriya Tomova 6-1 6-0.