Roddick injured his foot during the practice yesterday and decided to pull out ahead of his match against Wang Yeu-tzuoo.

"I woke up this morning and it felt OK," Roddick said. "But when I practiced, it happened again. I'm going to get back as soon as possible to start my recovery."

Roddick joins a list of top-ranked players who have withdrawn from the tournament. Second-ranked Rafael Nadal withdrew Sunday with a knee injury, followed by No. 3 Novak Djokovic, citing a bad back.

Roddick, ranked No. 5, helped the United States beat Sweden in the Davis Cup semifinals last weekend. Roddick defeated Jonas Bjorkman in straight sets Sunday in a clinching victory that carried the United States into the finals. The U.S. will play defending champion Russia for the title in November.

Berdych helped the Czech Republic defeat Switzerland in the Davis Cup playoffs over the weekend.

The 10th-ranked Berdych won the last seven games to complete his first match against the top Thai junior in just 47 minutes.

"My problem is to get ready for the match because I just came here and didn't have much time to prepare," said Berdych, who will next play Mischa Zverev.

In the other first-round matches, qualifier Nick Lindahl rallied to upset American Sam Querrey 2-6, 6-4, 6-3. Fernando Verdasco cruised past American David Martin 6-2, 6-1, and Dimitry Tursunov outlasted Werner Eschauer 6-3, 3-6, 6-1.