WTA CHAMPIONSHIPS: NO. 1S ARE ALL TIED UP DAVENPORT, SHARAPOVA ARE EVEN AFTER TWO SETS.

Byline: Matthew Kredell Staff Writer

Experience has been the story at the WTA Championships, with tennis mainstays Lindsay Davenport and Mary Pierce running the show.

Maria Sharapova tried to add her youthful presence to the fray Thursday. In a battle between the only two players to hold the No. 1 ranking this year, Sharapova and Davenport were locked in a three-set tangle in Staples Center at press time.

Sharapova, the tournament's defending champion, won the first set 6-3 and was serving for the match in the second set when Davenport's experience paid off.

At deuce, Davenport came from behind in the point to scorch a forehand cross-court for the winner. Sharapova hit a backhand into the net to give Davenport her first break of the match and even up the set.

It was the first time all match that Davenport was able to handle the serve of Sharapova, who had seven aces in the first two sets. At the same time, Davenport had an uncharacteristic five double faults.

Davenport easily won her service game and put the pressure on Sharapova. The young Russian couldn't handle it, failing to win a point on her serve to give Davenport the set 7-5.

The last time Sharapova and Davenport played, at Indian Wells in March, Davenport dominated 6-0, 6-0.

This time was much different.

Sharapova hit a forehand cross-court winner in the fifth game of the third set to take back the lead.

Regardless of the outcome of her match, Davenport could clinch the No. 1 ranking in the world to end the season if Amelie Mauresmo won at least one set from Elena Dementieva in the late match.

Mauresmo taking one set would eliminate Kim Clijsters from making the semifinals. Heading into the tournament, whichever player advanced further between Davenport and Clijsters would hold the coveted end-of-season top spot.

Davenport was the first player into the semis Wednesday based on winning her first two matches in straight sets.

In the evening's first match, Patty Schnyder became the first player to be eliminated from making the semifinals despite beating Nadia Petrova 6-0, 5-7, 6-4.

Schnyder was knocked out when Sharapova won one set from Davenport. Two players from each of the two groupings advance to Saturday's semifinals. If two players have the same record, the tiebreaker is not head-to-head play but the percentage of sets each player won.

Schnyder cruised through the first set then fought off five set points before dropping the second set. She had fewer winners than Petrova but limited her unforced errors to 34, nine less than the Russian.

``I was going for my first victory in the (WTA) Championships, so I got nervous and couldn't play well anymore in the second set,'' Schnyder said. ``I needed a few games to get my confidence back in the third set, but then I played really well.''

Schnyder lost earlier in the tournament to Sharapova and Davenport. Serving for the match, she hit a strong serve and forced Petrova to hit a backhand into the net.

Matthew Kredell, [phone]

matthew.kredell(at)dailynews.com