MELBOURNE, Australia (AP) _ Top-seeded Lindsay Davenport easily advanced to the Australian Open semifinals today, with Venus Williams losing some of her beads, a penalty point and her temper.

While Davenport served immaculately and outrallied Williams in the 6-4, 6-0 victory, the match will be remembered for a strange twist in the second set when Williams' famous beaded hairdo cost her a game.

When some beads fell on the first point in the third game of the second set, umpire Denis Overberg ordered the point replayed. As Williams served on game point, more beads fell and Overberg gave the point to Davenport.

``You could see she was thrown off by what happened,'' Davenport said. ``She just collapsed in the last few games. Obviously a lot of focus is going to be on the bead incident, but I was up a set and a break at that point.''

Rules permit a player to drop anything worn, such as a hat, only once in a match, with the second violation costing a point.

On videotape of Williams' argument with the umpire, she can be heard shouting, ``There's no disturbance. No one is being disturbed. ... As if I was doing it on purpose. You see me pulling my hair and pulling them out?''

Overberg cited the rule and said, ``I can't guess if it's disturbing the opponent.''

Sweat rolled down Williams' face and her voice quavered as she demanded to talk with tournament referee Peter Bellenger, who backed the umpire.

She finally returned to the court with a shrieked ``Aaaaaargh!''

At the end of the match, she was booed for not shaking hands with the umpire.

Williams, who previously has lost beads during matches, said later: ``I don't think it was a very fair call. ... I have never had such treatment before from any other umpire.''

``I shouldn't have to change my hair,'' she said, adding that ``I guess (the rule) was never written for beads,'' but maybe she should ``fix them a little tighter.''

Davenport, who recalled losing a point once when her hat fell off twice in a match, said Williams was warned after the first loss of beads.

``You can hear them and see them a little bit,'' Davenport said of the beads. ``I'm not going to say it was a total distraction, but it is a little annoying. ... It's just things flying in the air that you're not supposed to be seeing.''

But it was Davenport's serve, powerful groundstrokes and new-found agility that decided the hour-long match.

``I lost because I didn't play as well and lost my focus,'' said Williams, 1-7 against Davenport. ``I failed to capitalize on a number of opportunities.''

Davenport, the U.S. Open champion, has not lost a set in a Grand Slam event since dropping her quarterfinal match at Wimbledon.

Williams dropped service in the third game on a wildly errant attempt at a drop shot. Otherwise, she played a fierce game, at one point pounding in an ace of 118 mph.

With Davenport serving at 5-4 for the first set, Williams gained four break points. Davenport held her composure, served out of trouble, and took the set when Williams hit a forehand long.

In the second set, Davenport broke in the first game with a sharply angled forehand serve return, staved off a break point in the next game, and gained a free game from Williams' bead violation. From that point on, Williams struggled, finally going out with a forehand long.

In the semifinals, Davenport will face France's Amelie Mauresmo, a former world junior champion who also is quick, can overpower opponents, has fixed her backhand problems and is not afraid of the top players.

Mauresmo, 19, the latest in a series of impressive teen-agers in women's tennis, beat 11th-seeded Dominique Van Roost of Belgium 6-3, 7-6 (7-3).

If she wins, Mauresmo would be the first unseeded woman to capture a Grand Slam event since Australia's Chris O'Neil won the 1978 Australian Open.

Mauresmo won the 1996 French Open and Wimbledon junior titles, and began shooting up the tour rankings last year, climbing from 109th to 29th. Along the way, she had victories over Davenport and No. 3 Jana Novotna.

``I think all the conditions are coming together for me to play well here. I'm far from France, it's also a good thing,'' Mauresmo said, explaining she felt the pressure of public expectations at home.

She also recently split with the French tennis establishment, and has been working with coach Christophe Fournerie for a month.

Van Roost, who hits some big shots herself, said that ``in the second set I think I played perfect, and she was just overpowering.''

``When you see her running all around the court and just playing everything back, it's hard,'' the Belgian player said. ``Every time I was putting pressure on her, she was slicing, and it is not an easy slice.''

In Wednesday's quarterfinals, two-time defending champion Martina Hingis faces Mary Pierce, and Steffi Graf will play Monica Seles.

Thomas Enqvist became the first man to reach the semifinals, beating Marc Rosset 6-3, 6-4, 6-4.

Although unseeded, the Swede has established himself as a favorite by beating the U.S. Open champion and runner-up _ Australians Patrick Rafter and Mark Philippoussis _ in earlier rounds.

He has won 13 matches so far this year.

Enqvist's next opponent will be either No. 7 Karol Kucera of Slovakia or 91st-ranked Nicolas Lapentti of Ecuador, who met later today.

The only two other surviving men's seeds _ No. 10 Yevgeny Kafelnikov and No. 15 Todd Martin _ play each other in a quarterfinal Wednesday. In Wednesday's other quarterfinal, Vince Spadea will face Germany's Tommy Haas.