By JOHN PYE
AP Sports Writer
MELBOURNE, Australia -- Andy Roddick is on the oddest of rolls at the Australian Open, and that's just fine with him.
When an odd-numbered year comes around, Roddick finds himself in the semifinals of the year's first major. This time he got there courtesy of defending champion Novak Djokovic, who retired Tuesday while trailing 6-7 (3), 6-4, 6-2, 2-1. A sore, cramping and fatigued Djokovic was undone in the quarterfinal by 95-degree heat.
Roddick previously made it to the Australian semis in 2003, 2005 and 2007. He would now like to take this sequence a step further and make it to the final. One problem: Roger Federer.
Federer routed Juan Martin del Potro of Argentina 6-3, 6-0, 6-0 in his quarterfinal and is now only two wins shy of tying Pete Sampras' record of 14 major titles.
Roddick has not beaten Federer in six Grand Slam meetings and is 2-15 career against the Swiss star. He has reason for encouragement though. He ended an 11-match losing stretch to Federer last April in Miami.
"You're dealing with a guy who's probably the greatest ever," said Roddick, whose only major title came at the 2003 U.S. Open. "I think it helps that I stopped a big streak against him last year in Miami. It's certainly not going to hurt at all."
Federer, seeded second, needed to recover from two sets down to beat Tomas Berdych to reach the quarters. He wasted no time moving into the final four, sweeping the last 13 games and eliminating the eighth-seeded against del Potro in 80 minutes. The match was so one-sided Federer started feeling sorry for the 20-year-old Argentine.
"The last couple games are not that much fun, let's put it that way," Federer said. "You want to almost put him out of his misery because you know how tough it is for him."
A large sign on a red-and-white Swiss flag in the crowd read: "Shhhh. Quiet. Genius at work."
Federer lost to Djokovic in the Australian semis last year, ending a 19-match winning streak at Melbourne Park. He was struggling at the time with mononucleosis, which lingered until midyear and contributed to his loss of the No. 1 ranking he held for 237 weeks.
Rafael Nadal, who beat Federer in the French Open and Wimbledon finals and then overtook him at No. 1, plays No. 6 Gilles Simon of France in the quarterfinals Wednesday.
Jo-Wilfried Tsonga, who upset Nadal in the semis last year before losing the final to Djokovic, faces No. 14 Fernando Verdasco. Verdasco, who helped Spain win the Davis Cup in Argentina in Nadal's absence, upset Andy Murray in the fourth round.
The women's quarterfinals Wednesday features a match between the only two major winners remaining in the draw. Serena Williams, who has nine Grand Slam singles titles, takes on 2004 U.S. Open winner Svetlana Kuznetsova.
Olympic gold medalist Elena Dementieva faces Carla Suarez Navarro, who upset Venus Williams in the second round, in the other match. Already set is an all-Russian semifinal between Olympic silver medalist Dinara Safina and Vera Zvonareva.
No. 3 Safina struggled past Australia's Jelena Dokic 6-4, 4-6, 6-4 Tuesday night, serving 11 double-faults and making 36 unforced errors. That ended Dokic's surprising run in her first major in three seasons -- the 2000 Wimbledon semifinalist started at No. 187 in the rankings and beat three seeded players.
Zvonareva ran off the last 11 games to oust 2007 Wimbledon runner-up Marion Bartoli of France 6-3, 6-0. She hasn't dropped a set en route to her first semifinal in 25 majors.
Roddick, seeded seventh, was stating to assert himself against Djokovic when the Serb succumbed to the scorching heat. He later complained of having little time to prepare after a 2:26 a.m. finish Monday in his fourth-round win over Marcos Baghdatis.
"Conditions were extreme today. It did affect more on me than him," Djokovic said. "I really tried my best, but sometimes you can't fight against your own body."
Roddick first noticed him struggling during a medical timeout in the third set.
"At that point, obviously he's hurting," he said. "When you know he's hurting, all you want to do is just deliver that knockout blow."
Roddick grew up in Texas and Florida and lost 15 pounds in an intense offseason season with new coach Larry Stefanki. He said he enjoyed the conditions.
Lucky for him. It's going to get even hotter. Forecasters expect temperatures of about 104 until Saturday.
Seven of the top eight seeded men have reached the quarterfinals. Murray, seeded fourth, is the lone absentee.
"I'm probably the least favored of anybody to make it to the semis here," Roddick said. "I'm just going to keep going and keep my head down and keep working."
At Wimbledon in 2004, Roddick lost to Federer in four sets.
"I threw the kitchen sink at him, but he went to the bathroom and got a tub," he said at the time. That was one of three Grand Slam finals he lost to Federer. He also took only six games of Federer in their last meeting in Melbourne, the 2007 semifinals.
Federer thinks Roddick doesn't get the credit he deserves for someone who has finished seven years in the top 10 and reached four Grand Slam finals.
"I'm excited playing Andy," Federer said. "I'm happy for him. He's doing well here again," Federer said. "Sometimes people expect him to win 25 Grand Slams. He's one of my generation who was able to stay at this level. ... That's rock solid."
He also thinks Roddick will enjoy a lift from his victory over Djokovic.
"That's why I'm excited to play against him and seeing him create an upset in a big tournament," Federer said. "That's what's kind of been missing for him in the big tournaments lately."