MELBOURNE -- It has become an all-too-familiar feeling for Lindsay Davenport.
The top-seeded Davenport extended her Grand Slam title drought to six years with a 2-6, 6-2, 6-3 Australian Open quarterfinal loss to Justine Henin-Hardenne yesterday.
''To get out there and play well, then slowly get worse as the match went on -- it's a bad feeling to have when you leave," said Davenport, 29.
After winning the Australian Open in 2000, Davenport slipped out of the top 10, talked about retiring, then revived her career by regaining the No. 1 ranking and making the finals here and at Wimbledon last year. But the constant throughout the past six years has been a failure to add to her three major championships.
She took on a new coach, Dave DiLucia, for this season and said yesterday, ''there's obviously still a lot of stuff that I need to get better."
The eighth-seeded Henin-Hardenne's win over Davenport was not shocking. The reigning French Open champion has beaten Davenport in all three of their meetings at Melbourne Park, including the fourth round in 2003 and the quarterfinals in 2004, when she went on to beat Clijsters for the title.
Henin-Hardenne's semifinal opponent will be 2004 Wimbledon champion Maria Sharapova, who ousted fellow Russian Nadia Petrova, 7-6 (8-6), 6-4, after fighting off two set points in an error-strewn tiebreaker.
WTA Championship winner Amelie Mauresmo was broken once in the first set before taking nine straight games in her 6-3, 6-0 win over Switzerland's Patty Schnyder.
On the men's side, Nicolas Kiefer advanced to the semifinals with a grueling and contentious, 6-3, 0-6, 6-4, 6-7 (7-1), 8-6 win over Sebastien Grosjean today.
Kiefer's in the final four for the first time in 35 majors after playing the longest match of the tournament -- 4 hours 48 minutes. Up next for him could be top-ranked Roger Federer. The 2004 Australian Open winner and reigning Wimbledon and US Open champion went into his night quarterfinal match against No. 5 Nikolay Davydenko on a 49-match winning streak on hard courts.
Kiefer was barely able to contain his emotions.
In a bizarre point at 40-30 in the 12th game of the fifth set, Kiefer tossed his racket over the net just after Grosjean -- serving to stay in the match -- hit a forehand into the net.
Grosjean immediately appealed for a hindrance ruling, but was denied by umpire Carlos Bernardes and then argued the point with Grand Slam supervisor Mike Morrissey -- without success.
When the point was confirmed for Kiefer, making it deuce, the crowd erupted with loud boos and whistling.
Had Bernardes decided the racket landed in the singles court while the ball was still in play, Kiefer would have lost the point.
In the end, Grosjean held the game, and had the bulk of the center court crowd behind him.
Kiefer already had been warned twice for using obscene language. One more code violation would have cost him a point.
He frequently questioned line calls, losing his cool as he lost the fourth-set tiebreaker and again when he was broken for a second time in the fifth set.
The 28-year-old German smashed a water bottle at the changeover, but recovered to break Grosjean again and get the match back on serve.
Grosjean had game points in the 14th game but Kiefer earned a match point with a pinpoint lob and clinched it when the Frenchman put a backhand volley into the net.
Fourth-seeded David Nalbandian advanced to the semifinals by winning the last 14 games in a 7-5, 6-0, 6-0 win over 33-year-old Frenchman Fabrice Santoro.
He next faces former junior world champion Marcos Baghdatis -- a 20-year-old Cypriot in his first major semifinal.
Baghdatis added a 6-4, 6-2, 4-6, 3-6, 6-3 win over No. 7 Ivan Ljubicic to his fourth-round upset of No. 2 Andy Roddick.