Petkovic books semi-final spot

The German, seeded third, came through a tight first set and did not lose a game thereafter as she claimed a 7-6 (7/2) 6-0 victory over the Slovakian sixth seed.

Petkovic will face Barbora Zahlavova-Strycova after the Czech thrashed Mona Barthel 6-2 6-2.

Fifth seed Carla Suarez-Navarro was a 6-3 6-2 winner over 2010 French Open champion Francesca Schiavone of Italy, while Karolina Pliskova beat Czech compatriot Lucie Safarova 7-6 (7/5) 6-3.