Williams has not lost since a three-set defeat to Meghann Shaughnessy in the quarterfinals of the Bank of the West Classic in July. She extended her winning streak on Monday with a 6-2, 6-2 rout of another countrywoman, qualifier Ansley Cargill.

The 21-year-old Williams is bidding for her third straight Grand Slam title. Last season, she won Wimbledon and the U.S. Open for the second consecutive year.

Third seed and three-time champion Martina Hingis of Switzerland, hoping to stretch a streak of her own here, faces German qualifier Greta Arn. She has reached the Australian Open championship match the last five years, winning her first three.

The 21-year-old Hingis, who dispatched Virginie Razzano of France, 6-2, 6-2, on Monday, ended her title drought last week at Sydney, but the five-time Grand Slam winner has not captured a major since winning here in 1999.

Another former champion, eighth seed Monica Seles of the United States, meets Cara Black of Zimbabwe. Seles is 38-2 lifetime in Melbourne, claiming the crown from 1991-1993 and in 1996.

No. 11 Silvia Farina Elia goes against Jennifer Hopkins of the United States; 13th seed Magdalena Maleeva of Bulgaria takes on Kveta Hrdlckova of the Czech Republic; and No. 15 Amanda Coetzer of South Africa encounters Rossana Neffa-De Los Rios of Paraguay.

On the men's side, fourth seed Yevgeny Kafelnikov of Russia meets his second qualifier in a row in American Alex Kim. Kafelnikov, who defeated German's Michael Kohlmann on Monday, is the highest remaining seed left in the draw.

No. 1 Lleyton Hewitt lost on Tuesday, a day after second-seeded Gustavo Kuerten fell. Third seed and two-time defending champion Andre Agassi withdrew on Monday with a wrist injury.

This is the first Grand Slam since the 1990 French Open in which the top two seeds have lost in the first round.

Kafelnikov has not been beaten before the quarterfinals since his debut here in 1994. A year after capturing his second career Grand Slam title in 1999, he reached the final against Agassi.

Some of the 27-year-old Russian's greatest successes have come in Australia. He claimed the first of 24 singles titles at Adelaide in January 1994 and won the 2000 Olympic gold medal in Sydney.

With Hewitt, Kuerten and Agassi gone, Wimbledon champion Goran Ivanisevic is the only reigning Grand Slam title winner left in the men's draw.

Ivanisevic, who is putting off surgery on his sore left shoulder to play two more years, plays his 30th career match at the Australian Open against Jerome Golmard of France.

The 10th seed from Croatia could not gain entry into last year's main draw and lost in the first round of qualifying. If that moment was a low point for Ivanisevic, then he soared to his highest six months later when he captured his first Grand Slam crown at the All-England Club.

Fifth seed Sebastien Grosjean of France, a semifinalist here and at the French Open last year, plays Francisco Clavet. Clavet is the second Spanish opponent for Grosjean, who defeated Juan Balcells in the first round and is 2-0 lifetime against Clavet.

Also, sixth seed Tim Henman of Britain squares off against Vladimir Voltchkov of Belarus; No. 12 Guillermo Canas of Argentina battles Ramon Delgado of Paraguay; and No. 16 Thomas Johansson of Sweden encounters Austrian Markus Hipfl.