Defending champion Nikolay Davydenko continued his comeback from a serious injury by taking just 58 minutes to cruise through to the third round of the German Open in Hamburg.

Still rebuilding after three months out earlier this year, Davydenko produced a dominant performance on serve to overwhelm Frenchman Florent Serra 6-3 6-1.

Seeds Tommy Robredo and Gilles Simon were both casualties however. Robredo, seeded 11th, lost 7-6 5-7 6-1 to Potito Starace, while ninth seed Simon went down 6-4 3-6 7-5 to Finland's Jarkko Nieminen.

Florian Mayer gave the home crowd something to cheer as he made it safely through to the third round with a 4-6 7-6 (2) 6-3 win over another seed, 15th seed Aleksandr Dolgopolov of the Ukraine.

First round action included victory for Julian Reister over Daniel Brands in the battle of German wild cards, with Argentinian pair Juan Ignacio Chela and Eduardo Schwank also advancing.