NEW YORK (AP) - If all tennis tournaments were played on hard courts similar to those at the U.S. Open, Patrick Rafter would be nearly unbeatable. Since they're not, he must diversify his game to dethrone Pete Sampras as the world's No. 1 player.

Rafter, who won his second straight U.S. Open title Sunday with a 6-3, 3-6, 6-2, 6-0 victory over fellow Australian Mark Philippoussis, has been dominant during the hard-court season this summer. He has a 25-2 record since Wimbledon.

Perhaps the quickest player in tennis, Rafter used his speed on the ultra-fast Arthur Ashe Stadium court to nullify Philippoussis' power. Rafter is undefeated on that court since it debuted two years ago.

``When I move well, I play well, and I move so well on this kind of surface,'' Rafter said. ``My game goes hand in hand with my movement.''

The win moved Rafter past Marcelo Rios to No. 2 in the world, but Rafter knows overtaking Sampras for the top spot will not be possible unless he improves his game on other surfaces.

``To be No. 1 in the world, you can't play on this surface all the time,'' he said. ``I've adapted my game to this surface. I have to get that out of my mindset if I want to rival Pete at the top.''

Rafter defeated Sampras, who was hobbled by a strained quadriceps for the second half of the match, in five sets in the semifinals. He also defeated Sampras earlier this summer in a hard court tournament at Cincinnati.

``Patrick's one of the best serve and volleyers we have in the game,'' Sampras said. ``He moves very well. He's tough to break.''

Rafter's victory means four different men and four different women won the Grand Slam titles this year - showing the depth of talent in tennis.

``The most amazing thing is that it happened on the women's side,'' Rafter said. ``It's starting to become a bit more competitive on the women's side.''

By losing in the semifinals, Sampras failed to match Roy Emerson's record of 12 Grand Slam singles titles and Jimmy Connors' mark of five U.S. Open titles.

Sampras, who won at Wimbledon this summer, was the only American man to reach the quarterfinals of a Grand Slam tournament this year. For the second straight year, he also was the only American men's quarterfinalist at the U.S. Open. Before last year, that had not happened since 1986.

Andre Agassi's comeback stalled at the U.S. Open, where he lost in the fourth round to Karol Kucera. The future hope of American men's tennis, Jan-Michael Gambill, lost in the third round.

On the women's side, the outlook is much brighter for Americans. Lindsay Davenport won her first Grand Slam title with a 6-3, 7-5 victory over top-ranked Martina Hingis and moved back to No. 2 in the world.

Davenport had defeated fifth-seeded Venus Williams in the semifinals. Serena Williams also continues to improve and move closer to the elite ranks of women's tennis.

``A lot of people have said for a lot of years, `Oh, American tennis, especially women's tennis, there's no hope, there's no future,' '' Davenport said.

``I think it's looking better than ever. It's a tremendous accomplishment for me to win here, and I think there's going to be many more American champions in the next year with the Williams sisters and so many great players coming up.''