Hamburg, Germany –  Second seed and reigning champion Gilles Simon and former top-five star Nikolay Davydenko were among Monday's first- round winners at the $1.1 million German Tennis Championships.

The French Simon came from behind to beat Argentine Carlos Berlocq 4-6, 7-6 (7-5), 6-1, while the Russian Davydenko fought back to best Finland's Jarkko Nieminen 5-7, 6-4, 6-0 on the red clay at Rothenbaum Tennis Arena. Davydenko titled here three years ago.

Simon beat Spaniard Nicolas Almagro, this week's top seed, in last year's Hamburg finale. Almagro was the runner-up in Bastad, Sweden last week.

Also on Day 1 in Hamburg, qualifier Daniel Munoz-De La Nava defeated fellow Spaniard Ruben Ramirez Hidalgo 1-6, 6-4, 6-3, Argentine qualifier Federico Delbonis topped former top-10 Spaniard Tommy Robredo 5-7, 6-0, 6-1, and Dutchman Robin Haase cruised past German wild card Matthias Bachinger 6-4, 6-2. The on-the-mend Robredo titled here in 2006.

Last week's Stuttgart runner-up Juan Monaco of Argentina and last week's Umag champ Marin Cilic of Croatia are also in this week's draw.

The 2012 Hamburg champion will collect $265,000.