Nurnberg, Germany (SportsNetwork.com) - Second-seeded German favorite Angelique Kerber was among Tuesday's second-round winners at the Nurnberg Cup tennis event, a final clay-court French Open tune-up.

The in-form left-hander grounded Czech Klara Koukalova 6-1, 7-6 (7-2) at Tennis-Club 1.FC Nurnberg.

Kerber is seeking her third clay-court title of 2015, having already prevailed in Charleston and Stuttgart.

In other action involving seeds, No. 4 Italian Roberta Vinci mauled Czech Tereza Smitkova 6-2, 6-1, No. 6 Italian Karin Knapp clipped German wild card Anna-Lena Friedsam 6-1, 6-3 and No. 7 Japanese Kurumi Nara subdued Swiss Stefanie Voegele 6-3, 6-4.

One other Day-3 result saw Japanese qualifier Misaki Doi overcome China's Zhang Shuai 1-6, 6-3, 6-1. Doi will face Kerber in the quarterfinals.

On Wednesday, third-seeded German Sabine Lisicki will take on Spaniard Lara Arruabarrena in the second round.