The third-seeded American brings the hottest act in tennis to prime time as the $15 million U.S. Open gets under way today.

Williams must be considered the heavy favorite for the year's final Grand Slam as she rides a four-tournament winning streak into New York. Her incredible run started at Wimbledon, where she defeated Martina Hingis, younger sister Serena and Lindsay Davenport in consecutive matches to capture her first career Grand Slam singles title.

The 20-year-old Williams dominated the summer hardcourt season, winning titles at the Bank of West Classic, Acura Classic and Pilot Pen Tennis events.

A finalist here in 1997, Williams is 24-3 in seven tournaments since returning from a four-month layoff due to tendinitis in both wrists. She takes a 19-match winning streak into tonight's meeting with Anne-Gaelle Sidot of France.

Men's top seed Andre Agassi of the United States begins defense of his title with less confidence against countryman Alex Kim, who won the NCAA crown for Stanford this year.

Agassi, the two-time champion, has not won a title since capturing his sixth Grand Slam crown at the Australian Open in January.

Agassi reached the semifinals at Wimbledon but was in a minor car accident shortly upon returning to Las Vegas, injuring his back. He is 19-6 on hardcourts this season, advancing to the final at last week's Legg Mason Tennis Classic and the semifinals of the Ericsson Open.

Four other former champions are in action today.

Fourth seed Pete Sampras of the United States plays Martin Damm of the Czech Republic. Sampras became the all-time leader in Grand Slam titles at Wimbledon, where he claimed his record 13th major and record-tying seventh men's crown. He also won the Ericsson Open title on hardcourts in April.

The 28-year-old Sampras won his first career Grand Slam title at Flushing in 1990 -- the first of four U.S. Open crowns -- but has not won here since 1996. He did not play at this event last season after injuring his back in practice. Sampras is 52-7 lifetime at the U.S. Open.

Women's No. 1 Martina Hingis of Switzerland faces Alina Jidkova of Russia. Hingis has not won a Grand Slam title this season, but is a winner of five titles in 2000, compiling a 53-8 record. She was runner-up at the Australian Open and advanced to the French Open semifinals and Wimbledon quarterfinals.

The 1997 winner went 8-2 in the summer hardcourt season, winning the du Maurier Open two weeks ago.

Sixth seed Monica Seles, who captured the crown here in 1991 and 1992, meets fellow American Tracy Almeda-Singian. Seles reached the finals of her last two tournaments, losing to Venus Williams each time.

Arantxa Sanchez-Vicario, the ninth seed from Spain, goes against South African Joanette Kruger. Sanchez-Vicario has not won a title this season but is a threat on any surface, particularly in this year's majors. She reached -- the quarterfinals at the Australian Open, the semifinals at the French Open and the fourth round at Wimbledon.

In other first-round women's matches, eighth seed Nathalie Tauziat of France battles Ludmila Cervanova of Slovakia, 11th-seeded Sandrine Testud of France takes on Nicole Pratt of Australia, and No. 13 Amanda Coetzer encounters American Sandra Cacic.

No. 15 Jennifer Capriati of the United States plays Emmanuelle Gagliardi of France. The former teenage sensation, who is seeded at the U.S. Open for the first time since 1993, made an emotional exit last year after losing to Monica Seles in the fourth round when she was asked repeated questions about her troubled past. She advanced to the U.S. Open semifinals at age 15 in 1991.

On the men's side, fifth-seed Yevgeny Kafelnikov of Russia, a semifinalist here last year, faces Orlin Stanoytchev of Bulgaria; ninth-seed Lleyton Hewitt of Australia, who is tied for the ATP Tour lead in titles this season with four, takes on Andreas Vinciguerra of Sweden; No. 11 Tim Henman of Britain meets Fernando Vicente of Spain; No. 13 Franco Squillari of Argentina squares off against Juan Antonio Marin of Costa Rica and No. 16 Nicolas Lapentti of Ecuador goes against American Bob Bryan.