Sixth-seeded Luis Horna needed three sets to dispose of Daniel Koellerer in first-round action of the Internationaler Grand Prix. The Peruvian Horna dropped the first set against Koellerer, but rallied to defeat his Austrian opponent 4-6, 6-2, 6-4. In the only other match on Sunday, Sjeng Schalken of The Netherlands defeated American Kevin Kim 6-3, 2-6, 6-3. Schalken will face the winner of Monday's match between top seeded Nikolay Davydenko and qualifier Michal Mertinak in the second round. This event serves as a tuneup for the French Open, which gets underway on May 23 in Paris.