Philipp Kohlschreiber began the defense of his Gerry Weber Open title with a win over wild card Dustin Brown in an all-German matchup Monday.
The 163rd-ranked Brown twice pushed Kohlschreiber to a tiebreaker before the eighth-seeded defending champion won 7-6 (4), 7-6 (4) in 1 hour, 23 minutes.
Canada's Milos Raonic, the other seeded player in action on the opening day of the grass-court tournament, defeated last year's runner-up, Philipp Petzschner. The fifth-seeded Raonic had 19 aces to beat the German 7-5, 7-6 (1), setting up a second-round match with Ze Zhang of China, who beat another German, Tobias Kamke, 6-4, 7-6 (2).
Kohlschreiber will face Lukas Kubot after the Pole beat Jarkko Nieminen of Finland 6-4, 6-4.
Mikhail Youzhny of Russia beat Dutchman Robin Haase 6-3, 6-2, and Germany's Cedrik-Marcel Stebe defeated Argentina's Carlos Berlocq 6-3, 3-6, 7-5.
Rafael Nadal, who won his record seventh French Open title earlier Monday, and Roger Federer both have byes to the second round.