ESPN 2009 Australian Open

MELBOURNE, Australia -- Novak Djokovic abruptly surrendered his Australian Open title on Tuesday when he wilted in the Melbourne heat. But sympathy was in short supply from his fellow players -- particularly Roger Federer.

Djokovic, the No. 3 seed, threw in the towel midway through the fourth set of his quarterfinal with Andy Roddick, trailing 6-7 (3), 6-4, 6-2, 2-1. But in pointed comments, Federer, the No. 2 seed, noted that it wasn't the first time Djokovic has withdrawn midway through a match in a Grand Slam.

"He's not a guy who's never given up before ... it's disappointing," said Federer, who will face Roddick in the semifinals. "I've only done it once in my career ... Andy totally deserved to win that match."

"I'm almost in favor of saying, you know what, if you're not fit enough, just get out of here," Federer added. "If Novak were up two sets to love I don't think he would have retired 4-0 down in the fourth. Thanks to Andy that he retired in the end. Andy pushed him to the limits. Hats off to Andy."

Djokovic, 21, was the fourth player to quit in mid-match in two days, saying he was cramping and sore, as the on-court temperature at Rod Laver Arena soared above 104 degrees Fahrenheit (40 degrees Celsius). He had lamented that he didn't get to sleep until 6 a.m. Monday after his previous match against Marcos Baghdatis ended at 2:26 a.m. Monday, costing him practice time. He said he had requested another night match.

"Didn't really have time to recover," Djokovic said. "Conditions were extreme today. It did affect more on me than him, as you could see. But, you know, that was the situation. I just have to cope with it. Really tried my best, but sometimes you can't fight against your own body."

But it was the not the first time Djokovic had retired during a Grand Slam match.

In 2006, Djokovic retired from his French Open quarterfinal against Rafael Nadal after losing the first two sets. In 2007 he abandoned his Wimbledon semifinal contest against Nadal, blaming a toe blister.

Djokovic's habit of calling for a trainer on court has often irked his opponents. He was once rebuked by Federer in a Davis Cup clash between Serbia and Switzerland after taking what Federer felt was an unnecessary injury time out. And last September at the U.S. Open, an exasperated Roddick said of him, "He's either quick to call a trainer or he's the most courageous guy of all time."

On Tuesday, he became the first men's champion to quit while defending his title since Pat Rafter at the 1999 U.S. Open.

"I did have some retirements but I always retired with a reason. I don't see why anybody should [criticize me]," said Djokovic, who became the first Serbian man to win a Grand Slam title in Melbourne last year. "Whenever I retired, I retired because I felt I cannot go on."

Reuters and The Associated Press contributed to this report.