HALLE, Germany(AP) Tommy Haas has won his opening-round match at the Gerry Weber Open, defeating Stefan Koubek 6-2, 6-2.

Haas gave Roger Federer a scare in the French Open by going up two sets before the Swiss star rallied to win the fourth-round match.

Also Monday, fifth-seeded Tomas Berdych advanced with a 6-4, 7-5 win over Jan Hernych and sixth-seeded Dmitry Tursunov beat Igor Kunitsyn 7-5, 6-4.

Federer is scheduled to compete in the grass-court event, but says he's `mentally drained and exhausted'' after winning the French Open and may pull out. A decision is expected Tuesday.