NUREMBERG, Germany (AP) — Two-time champion Kiki Bertens began her Nuremberg Cup defense by beating Serbian qualifier Dejana Radanovic 6-1, 6-1 on Monday.

Second-seeded Julia Goerges saved a match point but was upset by Kristyna Pliskova 6-2, 6-7 (8), 7-6 (5) in 2 ½ hours.

Bertens had no difficulties as she made it 13 wins in a row at the clay-court tournament. The Dutch player next faces Carina Witthoeft or Mona Barthel.

Also, the fourth-seeded Zhang Shuai lost to Hungarian qualifier Fanny Stollar 6-2, 6-2, and Johanna Larsson of Sweden progressed against the fifth-seeded Irina-Camelia Begu, who retired with a left leg injury while trailing 6-4, 3-3.

Other winners included the eighth-seeded Katerina Siniakova, Alison Riske, and qualifier Nadia Podoroska.