NUREMBERG, Germany (AP) — Top-seeded Andrea Petkovic retired with an injury during her opening match at the Nuremberg Cup on Monday, while fellow Germans Angelique Kerber and Sabine Lisicki advanced to the second round at the clay-court tournament.
Petkovic retired when she was 5-0 down to Julia Putintseva of Kazakhstan with what appeared to be a right thigh problem.
Earlier, the second-seeded Kerber defeated Rebecca Peterson of Sweden 7-5, 6-4 and the third-seeded Lisicki defeated Silvia Soler-Espinosa of Spain 6-4, 7-5.
Kerber next faces the Czech Republic's Klara Koukalova, who defeated Germany's Annika Beck 6-4, 7-6 (6), while Lisicki plays Lara Arruabarrena for a place in the quarterfinals. The Spanish player defeated Hungary's Timea Babos 6-2, 7-5.
Japanese qualifier Misaki Doi upset the fifth-seeded Anna Karolina Schmiedlova of Slovakia 6-2, 6-1, while eighth-seeded German Carina Witthoeft defeated Belgian qualifier Alison Van Uytvanck 6-7 (2), 6-3, 6-3.
Also Monday, Anna-Lena Friedsam defeated fellow German Tatjana Maria 6-4, 6-4, Stefanie Voegele of Switzerland beat Renata Voracova of the Czech Republic 6-7 (3), 6-4, 6-2, Tereza Smitkova of the Czech Republic ousted Romanian qualifier Andreea Mitu 6-1, 3-6, 6-3, and Kiki Bertens of the Netherlands defeated Kazakhstan's Yaroslava Shvedova 6-1, 6-3.