MELBOURNE, Australia — Elena Dementieva got off to a fast start as temperatures soared Wednesday, advancing to the Australian Open semifinals with a 6-2, 6-2 win over Carla Suarez Navarro.

The Olympic gold medalist wasted no time as temperatures hit 104 degrees, winning 16 of the first 18 points against the 20-year-old Spaniard.

She raced through the first five games in 22 minutes and, after eventually holding serve in a sixth game that went to deuce 11 times and lasted 17 minutes, finished off in 1 hour, 35 minutes.

Dementieva was having problems with her high service toss as she looked straight up into the midday sun, double-faulting four times in that long game. She finished with 10 double faults.

Both players were soon draping towels packed with ice around their necks during changeovers and sought shade as long as possible behind the baselines between points.

Suarez Navarro, who had an upset second-round win over seven-time Grand Slam winner Venus Williams, tied her best run at a major — her quarterfinal debut at the last French Open.

Fourth-seeded Dementieva had never gone past the fourth round in 10 previous trips to Australia. Now she's only one win from reaching a third Grand Slam final. The 27-year-old Russian lost the French and U.S. Open finals in 2004.

She'll play the winner of Wednesday's later quarterfinal that features the only two major winners remaining in the draw.

Serena Williams, who has nine Grand Slam singles titles including one in Australia every alternate year since 2003, takes on 2004 U.S. Open winner Svetlana Kuznetsova.

Already set is an all-Russian semifinal between Olympic silver medalist Dinara Safina and Vera Zvonareva, who ran off the last 11 games to rout 2007 Wimbledon finalist Marion Bartoli 6-3, 6-0.

No. 3 Safina overcome 11 double faults and 36 unforced errors to end the surprising run of Jelena Dokic 6-4, 4-6, 6-4.

Andy Roddick continued his roll, reaching the semifinals in Australia to go with his previous runs to the final four at Melbourne in 2003, '05 and '07.

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 wants to go a step further but has one problem: Roger Federer.

Federer routed Juan Martin del Potro of Argentina 6-3, 6-0, 6-0 in his quarterfinal and is 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."

No. 2 Federer swept the last 13 games and eliminating the eighth-seeded against del Potro in 80 minutes.

Federer lost to Djokovic in the Australian semis last year, when he was struggling with mononucleosis that lingered until midyear.

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 later Wednesday.

Jo-Wilfried Tsonga, who upset Nadal in the semis here last year before losing the final to Djokovic, faces Spanish Davis Cup winner Fernando Verdasco.