Hingis, the defending champion, beat American wild card Alexandra Stevenson, 6-3, 6-4, Saturday to advance to the second round. Schnyder needed three sets to get past Australian qualifier Alicia Molik.

Hingis had her 12-match winning streak stopped last week by French teenager Amelie Mauresmo in the quarterfinals of the Open Gaz de France in Paris. Hingis defeated Mauresmo in the Australian Open final earlier this year.

The 18-year-old Hingis has reached the final in three of four events this year. She claimed her third straight Australian Open crown in January and returned to the top of the WTA rankings by winning the Pan Pacific Open in Japan last month. Hingis also was a finalist at the Sydney International in Australia in January.

Schnyder, 20, won five tournaments in 1998 but has caused more of a stir this year for splitting with her family, coach, and boyfriend in order to travel with 42-year-old mental and physical trainer Rainer Harnecker.

She and Hingis, who paired to help Switzerland reach the Federation Cup final, met twice last year. Schnyder earned a victory last October at the Grand Slam Cup when Hingis was fored to retire with an injury. Hingis got revenge at the year-ending Chase Championships with a three-set victory.

Three other third-round battles take place earlier today. Third seed Monica Seles of the United States, competing at this event for the first time since winning the title in 1992, plays Slovakia's Henrieta Nagyova; seventh seed Amanda Coetzer of South Africa, a two-time finalist, meets American Chanda Rubin; and No. 8 Nathalie Tauziat of France battles countrywoman Sandrine Testud, the 12th seed.

Seles has reached the semifinals in both tournaments she has played this year, losing to Hingis at the Australian Open and to Coetzer at the Pan Pacific Open. The former world No. 1 also reached the final here in 1991.

First prize is $800,000.