HALLE, GERMANY - JUNE 11: Philipp Kohlschreiber of Germany plays a forehand in his first round match against Dustin Brown of Germany during day one of the Gerry Weber Open at Gerry Weber Stadium on June 11, 2012 in Halle, Germany. (Photo by Dennis Grombkowski/Bongarts/Getty Images)

HALLE, Germany – Philipp Kohlschreiber began the defence of his Gerry Weber Open title with a win over wild card Dustin Brown in an all-German matchup on Monday.

The 163rd-ranked Brown twice pushed Kohlschreiber to a tiebreak, 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 playing on the opening day of the grass-court tournament, defeated last year's beaten finalist, Philipp Petzschner.

Fifth-seeded Raonic served 19 aces to beat the German 7-5, 7-6

(1), setting up a second round clash with Ze Zhang of China, who overcame another German, Tobias Kamke, 6-4, 7-6 (2).

The 28-year-old Kohlschreiber will face Lukas Kubot after the Pole beat Jarkko Nieminen of Finland 6-4, 6-4.

Kohlschreiber was relieved to see off Brown's challenge - Brown served two aces in succession to take the second set to the tiebreaker - and admitted that nerves had played a role.

“Then I struck the ball very well and I can also be happy with my return,” Kohlschreiber said.

There were wins too for Mikhail Youzhny of Russia, who beat Dutchman Robin Haase 6-3, 6-2, and Germany's Cedrik-Marcel Stebe, who defeated Argentina's Carlos Berlocq 6-3, 3-6, 7-5.

Rafael Nadal, who won his record seventh French Open title earlier Monday, and five-time winner Roger Federer both have byes to the second round. – Sapa-AP