Second-seeded Ivo Karlovic of Croatia beat Philipp Petzschner 6-3, 7-6 (7/3) to reach the second round of the Delray Beach International Tennis Championships on Tuesday.

Third-seeded German Benjamin Becker also advanced by defeating Japan's Kei Nishikori 6-3, 1-6, 6-0.

Defending champion Mardy Fish advanced when Belgian Christophe Rochus retired at 3-3 in the third set with a back injury.

Fish served up 25 aces against Rochus as he rallied to take the score to 5-7, 6-3 after two sets.

Fourth-seeded Jeremy Chardy of France advanced with a 6-3, 7-6 (7/5) victory over former two-time champion Xavier Malisse of Belgium.

Sixth-seeded German Florian Mayer beat Australian qualifier Nick Lindahl 6-4, 6-1.