Andy Roddick will aim to upset form and the history books on Thursday when he faces long-time rival Roger Federer in the first Australian Open semi-final.

The American faces world number two Federer for a place in the final in the knowledge that only twice in 17 matches has he overcome the 27-year-old Swiss.

"You're looking at a guy who's probably the greatest ever," said Roddick, "but I don't want any regrets."

The pair's match follows the women's semi-finals in the Rod Laver Arena.

Fourth seed Elena Dementieva is first on court against American second seed Serena Williams, with Dinara Safina facing fellow Russian Vera Zvonareva in the second match.

Dementieva and Williams will be hoping they recover sufficiently after having to play their respective quarter-finals in the searing Melbourne heat on Wednesday.

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The Russian came through her match against the tournament's surprise package Carla Suarez Navarro 6-2 6-2, before Williams beat Svetlana Kuznetsova 5-7 7-5 6-1 after the roof was closed midway through their match because of the heat, which peaked at 43C.

Safina and Zvonareva, who played their quarter-finals on Tuesday, should be in better shape, but the match is still a tough one to call with the third seed boasting a narrow 5-4 winning record in matches between the pair.

However, Zvonareva, seeded seventh, has won the last three matches and will fancy her chances on the hardcourt surface.

Which is more than can be said of Roddick, who as a one-time Grand Slam winner is tasked with halting Federer's progress towards a record-equalling 14th Slam title and a fourth Australian Open crown.

Roddick won their last meeting in Miami last year and is feeling more upbeat about his chances.

"I think it helps that I stopped a big streak against him last year," he said.

Fifth seed Laura Robson will be hoping to add to her Wimbledon title

"The thing about Roger, one of the things that makes him great, is he makes that very difficult."

As well as winning the US Open in 2003, Roddick has been runner-up three times since: at Wimbledon in 2004 and 2005 and in New York in 2006.

Each time Roddick's conqueror has been Federer, but the American is in no mood to give up, saying: "I'm 26-years-old. What the hell else am I going to do with myself?

"That's obviously the motivation behind it. The other thing is you just don't want to look back on the your career with regrets."

And Federer, who is chasing Pete Sampras's Grand Slam title record, insists he will be taking nothing for granted.

"He beat me last time we played. Maybe now he's in better shape I should have no chance. It's a tennis match. You never know what is going to happen. That's why it starts at 0-0.

"I'm excited playing Andy. I'm happy for him. He's doing well here again."

If you are in the UK, you can follow the match live on the Red Button, the BBC Sport website and 5 Live sports extra.

The second semi-final between Spaniards Rafael Nadal and Fernando Verdasco will take place on Friday.

Meanwhile, British duo Laura Robson and Heather Watson are also in action on day 11 of the tournament.

Londoner Robson will now face Romania's Elena Bogdan, while Guernsey's Watson faces Russian third seed Ksenia Pervak, in the quarter-finals of the girls' singles.