Top-seeded David Ferrer withdrew from the grass-court Topshelf Open on Monday and warned he might not play at Wimbledon.

Ferrer, who lost to Rafael Nadal in last year's French Open final, withdrew because of stomach problems without playing a match.

"I'm not sure if I can play at Wimbledon," Ferrer said, adding he came down with flu after Roland Garros. "I'm going to talk with my doctor in Valencia tomorrow and see. It's been 10 days now, and that's just too long for this problem."

In first-round action, fifth-seeded Dmitry Tursunov of Russia beat Bradley Klahn of the United States 6-3, 7-6 (3).

Tursunov had little trouble in the first set, but each player had a break in the second to set up the tiebreaker which Tursunov won easily.

The men's event includes defending champion Nicolas Mahut of France while French Open finalist Simona Halep is the top-seeded player in the women's tournament.

Meanwhile, wild-card Michaella Krajicek had two victories of a sort on Monday. First, she beat Jana Cepelova 6-3, 4-6, 6-1.

Then her boyfriend, German doubles player Martin Emmrich, overcame an early set of nerves and proposed to her on center court.

With a shaky voice he called her "Bambi," got down on one knee and asked, "Will you marry me?"

The 25-year-old Krajicek, who had been standing covering her mouth in shock, giggled and agreed. They plan to compete in the mixed doubles at Wimbledon.