Roddick out of Australian Open with injury

MELBOURNE, Australia -- Andy Roddick lunged for a shot by Lleyton Hewitt and felt a sharp pain in his right leg. He stayed down on his hands and one knee for a few seconds, wondering if his Australian Open was finished.

He played the next two points, falling behind 3-0 in the second set, before taking a medical timeout to treat his hamstring.

Still, Roddick played on. Clearly restricted, he didn't bother to chase down some shots and walked slowly between points with his head down.

Finally, after 16 more games, Roddick called it quits. He retired with Hewitt leading the second-round match 3-6, 6-3, 6-4.

"It's a miserable, terrible thing being out there compromised like that," Roddick said.

The 29-year-old American knew he wouldn't be able to fool an opponent he was playing for the 14th time, one of the few players on the tour older than he is, somebody who was ranked No. 1 before he was and someone with one more Grand Slam title.

"He's a tough guy to play," said Roddick, now 7-7 against Hewitt for his career. "You can try to ham and egg it against a lot of guys. But he's really intelligent. He knew what was going on.

"It's frustrating. It's discouraging," he said, referring to the hamstring injury. "You know, your sensible mind says to have a sense of perspective. You still have it pretty good. The competitor in you feels terrible and wants to break stuff."

Novak Djokovic, who won three of the four major titles last year, kept getting better in his 6-3, 6-2, 6-1 win over Santiago Giraldo. Andy Murray, who lost to Djokovic in last year's Australian final, ousted Edouard Roger-Vasselin of France 6-1, 6-4, 6-4. Five-time Australian Open champion Serena Williams notched her 500th career singles victory by beating Barbora Zahlavova Strycova 6-0, 6-4.

In a match early Friday, second-ranked Rafael Nadal had no trouble with Lukas Lacko, dispatching him 6-2, -6-4, 6-2.