The American siblings saw off rivals Chanda Rubin, also of the US, and Sandrine Testud of France with a 4-6 6-1 6-4 victory.

The sisters roared back following a disappointing start

Commenting on her new-found celebrity status, Serena said: "I had 21 messages on my cell phone and that's an all-time high.

"I'm very popular now."

The French Open champion Williams sisters won after roaring back from a disappointing first set.

They scored only five points in losing the first five games of the match, but then took 10 of the next 12 games on their way to their second 1999 Slam crown.

At 17, Serena finds herself in some fairly elite company, joining Margaret Court, Billie Jean King, and Martina Navratilova as the only women who have won the singles, doubles and mixed championships of the U.S. Open in their career.

Both Court (1970) and Navratilova (1987) won all three championships in the same year at the U.S. Open.

Serena's monumental efforts added up to $750,000 for the singles win and half of the doubles prize money of $330,000.

"I'm not a really celebrating person," Serena said. "I'll celebrate with my credit card."