SYDNEY, Australia (AP) -- Defending tournament winner Amelie Mauresmo withdrew from the Adidas International semifinals Friday, giving No. 2-ranked Lindsay Davenport a walkover into the final against No. 1 Martina Hingis.

A nagging back injury forced Mauresmo to abandon her match against Davenport. Mauresmo, who was sidelined for four months of the tour last year due to a back injury, had been scheduled to meet Davenport in a replay of last year's final of the Australian Open tuneup event.

Davenport goes into the title match against Hingis, who beat No. 4 seed Conchita Martinez of Spain 6-3, 6-2 in the other semifinal.

Davenport has a 12-9 edge over Hingis in head-to-heads since 1995. She also has the advantage in Australian conditions, having overcome Hingis in the 1999 Adidas International final and in last year's Australian Open final at their last two meetings in Australia.

Hingis, however, said she had an edge over Davenport because she was more match-hardened after her unbeaten run with Hopman Cup-winning Switzerland last week.

``I'm No. 1 and she's No. 2, so it's good to have a final like this,'' Hingis said. ``My standard right now is very high. I feel confident.''

Mauresmo said she consulted tournament medical officer, Dr. John Ackermann, after injuring her back in a quarterfinal win over third-seeded Monica Seles on Thursday.

The injury had not responded to further treatment, she said, although the 21-year-old Frenchwoman remained optimistic about playing in next week's Australian Open.

``It's not as bad as it was last year,'' she said. ``I hope the two or three days off are going to be enough for me to relax and let the pain go.''

Mauresmo, an Australian Open finalist in 1999, is seeded 13th for the season-opening Grand Slam tournament at Melbourne Park, where she was scheduled to meet Ai Sugiyama of Japan in the first round.

Mauresmo said the pain was caused by an inflammation between two bones in her spine, but it only bothered her on serves.

``What is tough is that it's only (painful) on the serve -- I can play the rest of my game and I feel good, so it's very frustrating,'' she said. But ``I can't go into a contest not knowing how I'll serve.''

In the men's semifinals, top-seeded Magnus Norman overcame heat, humidity and a pumped-up Jonas Bjorkman in an all-Swedish clash to advance to the final where he will meet the winner of the Lleyton Hewitt vs. Sebastien Grosjean semifinal.

Norman, ranked fourth in the world, dropped the first set but rallied to edge his compatriot 5-7, 6-3, 7-5 on his third match point.

Norman slumped to his haunches in exhaustion when Bjorkman sent a forehand volley just wide after 2 hours, 37 minutes of grinding tennis.

The temperature exceeded 95 degrees on center court, forcing organizers to cool players with portable electric fans during the breaks.

Women's tour officials introduced the Extreme Conditions Rule for the women's semifinal between Hingis and Martinez. That rule stipulates that when combined air temperature and relative humidity reaches 90 degrees, players are allowed a 10-minute break between the second and third sets to change clothes and cool down.