Roddick fresh as a daisy in extreme heat

MELBOURNE, Australia -- It wasn't bird flu, anthrax or SARS, just cramps and the baking heat.

Novak Djokovic, who entered the Australian Open dogged by a few questions about his preparation and new racket, leaves with as many after exiting to a rejuvenated Andy Roddick 6-7 (3), 6-4, 6-2, 2-1 in their quarterfinal grudge match on Rod Laver Arena.

Bye-bye to the defending champion and hello to a possible Roddick-Roger Federer rematch.

Roddick sarcastically joked that Djokovic suffered from the above ailments prior to their quarterfinal at the U.S. Open in September; the comment was precipitated by Djokovic's penchant for taking injury timeouts in previous rounds. A charged-up Djokovic responded with a four-set win in the quarterfinals that day, made a few enemies by publicly criticizing Roddick on his home turf, and subsequently got no support against Federer, a perennial crowd favorite.

Djokovic has a long history of retiring, and he began to wilt in the second set as on-court temperatures topped 105 degrees. Forced to take, uh, another medical timeout when he was down 2-1 in sets, Djokovic had his pulse taken and got a rub down. Snacking on bits of a banana and ingesting salt was the norm for the Serb on changeovers thereafter, but it didn't help. Finally, trailing Roddick 2-1 in the fourth, Djokovic said no mas.

Roddick didn't overly dis Djokovic this time -- he won, after all -- but was a tad puzzled.

"I looked over and I was confused, because I thought it was one injury per timeout, and I saw a calf, a neck and an arm," Roddick said. "But I guess cramping is one condition."

Tournament officials did Djokovic no favors. The Roddick-Djokovic tilt looked like the tastier Tuesday quarterfinal, and normally the better quarterfinal is scheduled at night. Further, Djokovic ended his fourth-round match against inconsistent Cypriot Marcos Baghdatis, the 2006 finalist, a whisker before 2:30 a.m. Monday. He went to bed at about 5:30 a.m. and didn't practice Monday, choosing to recuperate instead. Federer, coming off a five-set win over Tomas Berdych, beat rising Argentine Juan Martin del Potro in the night session.

"If you end up the match at 3 a.m., it's basically logical thinking that you should play the same match, second after 7:30 [p.m.],'' Djokovic said. Later, when pressed about why his request to play at night wasn't accepted, he added, "It was probably, I don't know, TV or things like that, some requests, other requests, which is, you know, a little bit disappointing."

Ironically, Djokovic benefited from the scheduling last year. He downed two-time Grand Slam champion Lleyton Hewitt in the last 16, a round after the feisty Aussie finished his previous match against Baghdatis at 4:30 a.m. the day before.

"I'd be disappointed if I was the defending champion, had a late finish, and all of a sudden was asked to play again in a day where the temperatures were also [100 degrees]," said Roger Rasheed, Gael Monfils coach and a local broadcaster for Channel 7. "You can see the weather three or four days in advance. And it probably was the tastier of the two semifinals, but I think every player at some stage in their career has been in a scheduling situation where they couldn't believe the situation."

Nevertheless, Roddick was fresh as a daisy. Training in sweltering conditions in Texas helps, as does losing 15 pounds in the offseason under new coach Larry Stefanki, who already appears to be working the magic previously applied to the likes of Russian Yevgeny Kafelnikov and Chileans Marcelo Rios and Fernando Gonzalez. Roddick moved into his second Grand Slam semifinal since the 2006 U.S. Open, both Down Under.

And how's this for symmetry? Roddick has made the semis here every other year starting in 2003.

"That's extremely coincidental," Roddick deadpanned.

All of a sudden, two of the big four are gone. Djokovic got it right when he said Andy Murray shouldn't be considered one of the favorites. The Brit, slightly ill, departed to the red-hot Fernando Verdasco on Monday. Djokovic included himself on the list of contenders, so he was a tad wrong there.

Djokovic's departure marked a fourth retirement in two days -- Victoria Azarenka of Belarus succumb to a virus while leading another American, Serena Williams; Zheng Jie suffered a wrist injury and bailed against Svetlana Kuznetsova; and Monfils cut short a promising all-French clash by calling it quits against good pal Gilles Simon due to a wrist injury.

"This is all part of the sport," Djokovic said. "I did have some retirements, but I always retired with a reason."

The sooner-than-anticipated ending Tuesday cut short a match that promised much drama, even if the entertainment factor lacked. Roddick reverted to his old style in the first set, choosing to hang well behind the baseline during rallies. Even though he made only three unforced errors and didn't face a break point -- neither did in the opener -- Djokovic dictated.

He raced to a big lead in the tiebreaker thanks to a lethal forehand. Djokovic hit almost identical inside-out forehands to make it 2-0, sent a tame one into an open court, then ripped another down the line. A delighted roar followed. The tennis gods gave Djokovic some help at 4-2, with a backhand return off a second serve skimming the top of the net and falling over.

Roddick altered his approach in the second set, going for more on returns and doing all the dictating. He's not going to lose much serving at 82 percent on first serves, either.

Mind you, Djokovic forewarned his retirement by throwing in two straight drop shots to start the seventh game, when the lone break resulted. The remainder of the match was mere formality.

Roddick trails Mr. Destiny, Federer, 15-2 in their head-to-heads. The good news for Roddick is that he's riding a one-match winning streak. Roddick overcame Federer at the Miami Masters last year.

"You know, I think it helps that I stopped a big streak against him last year in Miami," Roddick said. "It's certainly not going to hurt at all. I'm probably the least favored of anybody to make it to the semis here. I'm just going to keep going and keep my head down and keep working. I'm not going to get too excited."

Ravi Ubha is a frequent contributor to ESPN.com.