NEW YORK (Reuters) - Seventeen-year-old Serena Williams posted an historic Grand Slam triumph Saturday as she overpowered world No. 1 Martina Hingis 6-3, 7-6 to win the U.S. Open women's singles title.

The seventh-seeded Williams became the first black woman to win a Grand Slam singles crown since American Althea Gibson claimed the U.S. championship 41 years ago and the first black American to win a major title since Arthur Ashe won Wimbledon in 1975. When top seed Hingis' backhand sailed long for a 7-4 decision in the second-set tiebreaker, Williams clutched her heart and said ``Oh my God'' in wide-mouthed wonder to the wild cheers at Arthur Ashe Stadium.

``I didn't know what to do,'' the powerfully built Williams said about her winning moment. ``Laugh or cry or scream. I think I did it all.''

Williams used her dynamic serve to dodge danger as she turned away seven of the 10 break points held by Hingis in the match. The winner posted eight aces to run her tournament total to 62 -- nearly triple the next closest player.

The triumph capped a whirlwind rise up the ranks of women's tennis for Williams, who won her first professional title at the Paris Indoors just over six months ago.

The one hour, 42-minute victory was worth $750,000 to Williams, who soared to the title with an exhilarating Open run. She ousted second-seeded defending champion Lindsay Davenport in the semifinals and eliminated fourth-ranked Monica Seles, a two-time Open winner.

The top-seeded Hingis, who beat Serena's older sister Venus Williams in the semifinals, collected $420,000 as runner-up.

``I want to congratulate Serena on her first title here at the U.S. Open,'' said Hingis, the Australian Open champion and French runner-up said at the trophy celebration.

Hingis, the 1997 champion and owner of five Grand Slam titles, was playing her ninth major final and entered the match with $9 million more in career earnings than Williams, who had never before advanced past the fourth round of a major.

But the 18-year-old Swiss knows this marks the start of a most serious rivalry.

``It was a great match. I think we're going to have many years coming up against each other,'' said Hingis. ``I'm definitely looking for revenge next year.''

Playing in just her seventh Grand Slam tournament, Williams beat her 19-year-old older sister Venus to the punch by winning a Slam title and gained a measure of revenge for the family. Besides losing to Hingis in Friday's semifinals, Venus was runner-up to the Swiss in the 1997 Open.

Williams used her big serve to turn Hingis back time and again in the first set, escaping six break points. She shrugged off one in the first game and two more in the third game after breaking Hingis to lead 2-0. Four successive big serves from 15-40 allowed Williams to take a 3-0 lead. Another service winner squelched Hingis' hopes for a break in the fifth game.

The top seed finally brought the set back on serve in the seventh game, when she returned another big Williams serve to draw a backhand wide. But Williams broke back against a weak-serving Hingis in the next game and served out the set, saving two more break points on the way.

In the second set, three successive breaks of serve from the fifth game left Williams leading 5-3 after she finally held.

With Hingis serving, a backhand serve return winner and a forehand crosscourt winner gave Williams double match point at 15-40, but then nerves seemed to set in. Williams made four successive errors to squander that chance.

Hingis then broke Williams at love and the tide seemed to be turning.

``I actually was saying to myself, 'What am I doing out here?''' Williams recalled.

But in the 12th game, straining to force a tiebreaker, Williams denied Hingis a set point from deuce and eventually held on her fifth game point with a backhand winner off a stretching backhand volley from Hingis.

Once in the tiebreaker, Williams's supreme confidence returned.

``I feel like I can't lose in tiebreakers,'' said Williams, who is in fact unbeaten in the six tiebreakers she has played this year.

Grunting ferociously with each punishing groundstroke, Williams unleashed a winning service return for a minibreak to lead 5-4. This time, Williams did not waste her opportunity to serve for the match.

A powerful forehand drive induced a long lob from Hingis to reach match point number three at 6-4. When Hingis sailed a backhand long, the match was over, and some history was written by the young Williams.

Even Hingis appreciated the moment.

Asked what words she exchanged with the world No. 1 at the net, Williams replied, ``She said, 'Isn't this exciting!'''