Spanish qualifier Pere Riba posted the upset of the day at German Open with a 1-6, 6-0, 6-3 victory over last year's finalist Paul-Henri Mathieu of France on Monday.

Another Frenchman Florent Serra edged past Evgeny Korolev 7-6(7), 6-3 to set up a meeting with top seed and defending champion Nikolay Davydenko, while Jeremy Chardy defeated Switzerland’s Marco Chiudinelli 6-4, 6-1.

Italian duo Potito Starace and Fabio Fognini also reached the second round. Starace beat German qualifier Bjorn Phau 7-5, 6-0 and Fognini beat Spaniard Ruben Ramirez Hidalgo 7-6 (4), 6-4.

In other matches of the day, Florian Mayer of Germany beat Pablo Cuevas of Uruguay 6-4, 6-1, and Maximo Gonzalez of Argentina defeated Olivier Rochus of Belgium 6-4, 5-7, 6-2.

Second seed David Ferrer pulled out of the tournament with a right shoulder injury. He has been replaced by Marc Giquel of France.

Fourth seed Gael Monfils and Guillermo Garcia-Lopez have both withdrawn due to right ankle injuries.