Seeking her third title in four events this year, Hingis needed just 41 minutes to dispose of Yugoslavian qualifier Sandra Nacuk, 6-1, 6-1, and extend her winning streak to 12 matches.

Second seed Nathalie Tauziat of France, the oldest player in the draw at 31, continued her early-season skid as 17-year-old American Serena Williams, the youngest player in the draw, scored a 6-1, 6-4 second-round upset. Tauziat saw her 1999 record fall to 1-3.

Two seeds were straight-sets winners in first-round play. Sixth seed Amelie Mauresmo of France, who became the first unseeded player to reach the Australian Open final in 21 years, dumped countrywoman Laurence Andretto, 6-2, 7-5. Also, eighth seed Elena Likhovtseva of Russia defeated Sabine Appelmans of Belgium, 7-6 (7-4), 6-3.

In unseeded play, Croatia's Iva Majoli downed Elena Tatarkova of Ukraine, 7-5, 6-2; Virginia Ruano Pascual of Spain got past Japan's Ai Sugiyama, 6-1, 3-6, 6-1; Karina Habsudova of Slovakia rallied past Frenchwoman Emilie Loit, 3-6, 6-4, 6-1; and Sandra Kleinova of the Czech Republic stopped Alexandra Fusai of France, 6-2, 2-6, 6-0.

Making her first appearance here since winning the title in 1997, Hingis has reached the final in each of her three 1999 events, winning the Australian Open and the Pan Pacific Open in Tokyo after losing to Lindsay Davenport at the Sydney International. Today's victory improved her season record to 15-1.

Five seeds will play their second-round matches on Thursday. Third seed Dominique Van Roost of Belgium will take on Ruano Pascual; fourth seed Irina Spirlea of Romania will meet Amelie Cocheteux of France; Mauresmo will go against Habsudova; eventh seed and 1996 winner Julie Halard-Decugis of France will face countrywoman Anne-Gaelle Sidot; and Likhovtseva will play Kleinova.

Van Roost is appearing in her fifth event of 1999 and has an 11-4 match record, including a runner-up finish at last month's ASB Bank Classic in New Zealand.

The top four seeds received first-round byes.

First prize is $80,000.