India's teenager Sania Mirza fought hard before losing to Japan's Akiko Morigami 6-2, 4-6, 6-4 in a third round clash of the $1.3 million Acura Classic tennis tournament here Thursday.

Earlier, Sania had defeated fourth seed Nadia Petrova 6-2, 6-1 to enter the third round Wednesday at this golfing resort.

In other matches, Japan's Ai Sugiyama earned her first career win over Svetlana Kuznetsova Thursday as she knocked the US Open defending champion out in the third round of the tournament.

The two-hour, 21-minute upset at this southern California golfing resort marked a breakthrough for the 38th-ranked Japanese, who had lost twice to the Russian, the last time in the Roma third round in May.

The final set featured only one break of serve, with Sugiyama holding on to the margin she achieved at 2-all.

Sugiyama, 30, winner of six WTA titles, will Friday play a quarterfinal against unseeded Bulgarian Sesil Karatantcheva.

The teenager, who turns 16 on Monday, scored an easy win over American Mashona Washington 6-1, 6-2.

Karatantcheva's victory was her first quick outing of the week as she aims for an initial career trophy.

"I was staying calm and having fun," said the extroverted Karatancheva, ranked 49th, who put out the last American in the field. "The crowd was obviously for her, but I didn't let it bother me.

The quarter-final was the third for the teenager this year, a plateau which Karatancheva said she hopes to finally surpass at the WTA level.

Despite reaching the last eight at the French Open, where she lost to Elena Likhovtseva, the young talent is far from satisfied.

Russian Anna Chakvetadze, another of the emerging Russian teenaged brigade, upset elder compatriot Elena Likhovtseva, the ninth seed, 6-3, 6-1.

The run of form continued for China's Shaui Peng, who put out Russia's Dinara Safina 7-6 (7-2), 6-0.

Number 5 Patty Schnyder was leading a trio of European seeds playing later third-round matches as she took on Italy's Francesca Schiavone.

The Swiss, winner of a title last month in the US, is bidding to surpass Maria Sharapova for the most wins this season, as she bids for her 42nd.

Confident two-time Grand Slam winner Mary Pierce, the number 6, was taking on French compatriot Nathalie Dechy while tournament favourite Kim Clijsters, seeded seventh, was to play Jelena Jankovic.

RESULTS:

(x indicates new result):

Third round

Ai Sugiyama, Japan, def. Svetlana Kuznetsova, 2, Russia, 2-6, 6-
4, 6-3

x Patty Schnyder, 5, Switzerland, def. Francesca Schiavone, 17,
Italy, 6-7 (1-7), 6-1, 6-4,

x Kim Clijsters, 7, Belgium, def. Jelena Jankovic, 11,
Serbia-Montenegro, 6-1, 6-3

Anna Chakvetadze, Russia, def. Elena Likhovtseva, 9, Russia, 6-3, 6-1

Shaui Peng, China, def. Dinara Safina, 16, Russia, 7-6 (7-2), 6-0

Sesil Karatantcheva, Bulgaria, def. Mashona Washington, U.S., 6-
1, 6-2