NEW YORK (AP) The old, admittedly out-of-shape Mardy Fish won only 2 of 8 five-set matches he played at the start of his career.

The new, 30-pounds-lighter Fish has won 2 of 3, including a 6-0, 3-6, 4-6, 6-0, 6-1 victory over Jan Hajek of the Czech Republic in the U.S. Open's first round Tuesday.

I feel like a completely different player. I mean, I know that I am,'' said the 19th-seeded Fish, who has won 17 of his past 19 matches.So how far that takes me, I have no idea. But, you know, I've never been fitter and never been mentally as strong. I've never wanted it more, and so hopefully that goes a long way.''

Fish, who lives in Tampa, Fla., hit 24 aces against Hajek but found himself trailing 2-1 in sets.

It was a scary position to be in, no doubt about it,'' Fish said.This is a new position for me. It's new, sort of, to have a lot of expectations, have a lot of people talking about you. It's a new spot for me, and it's where we want to be, for sure.''

So what did Fish do Tuesday? Went out and took the last two sets in only 51 minutes.

The 6-foot-2 Fish weighed 203 pounds on Sept. 28, 2009, the day he had surgery on his left knee. Now he's slimmed down to about 170, thanks in part to new eating habits overseen by trainer Christian LoCascio.

In a recent interview, LoCascio recalled being at a tournament in Italy and watching Fish eat pizza as an appetizer before dinner or heaping mozzarella on a salad at lunch.

All of that kind of stuff was adding up, and he was ... just enjoying himself - enjoying himself off the court, maybe a little bit more than he needed to,'' LoCascio said.Once the knee injury happened, it all kind of hit home. The weight kind of was a contributing factor to it, and he saw it as something he could really attack and conquer and come out better for it.''

Fish's best U.S. Open result was a quarterfinal appearance in 2008, and he thinks he's capable of making that type of run again.

Nowadays, Fish said, he'll come across old pictures of himself, turn to his wife and ask, ``What was your problem? Why didn't somebody tell me that I looked like that?''


SOCK IT TO 'EM: There's been a lot of talk lately about what the future of U.S. tennis may hold. One young American will get a chance to introduce himself on a big stage Wednesday, when 17-year-old Jack Sock plays in the first round of the U.S. Open.

Sock, a high school senior who grew up in Lincoln, Neb., earned a wild card from the U.S. Tennis Association by winning the boys' 18s singles championship at the USTA national championships at Kalamazoo, Mich., on Aug. 15.

He'll face 63rd-ranked Marco Chiudinelli of Switzerland on Court 13, one of the five Flushing Meadows courts equipped for TV coverage.

My goal for my lifetime is I want to make a living playing this sport,'' Sock said.If that means top 50 or top 20 or whatever, that would be awesome.''

He hasn't decided whether to go to college - ``I'm going to see how the rest of this year goes,'' Sock said - and gave a long list of possible destinations, should he go that route: Texas, Virginia, Nebraska, Ohio State, Michigan, Oklahoma, Florida, Southern Cal.

He's a really, really good competitor, and he has a natural sense of the game,'' said Mike Wolf, who coaches Sock at a tennis academy in Kansas.He understands the geometry of the court.''

Sock said he got a chance to practice once with 2003 U.S. Open champion Andy Roddick, the last American man to win a Grand Slam singles title, and calls Roddick ``a great inspiration to watch; he works so hard.''

Sock also received a USTA wild card for the junior boys' tournament, so he'll get to play again in New York, no matter what happens against Chiudinelli.

I hope he wants to go out there and play to win, which he will, but the greatest part of it is not so much the experience of the playing a guy like Chiudinelli, but just the moment of being at a Slam and seeing how you match up at this point,'' Wolf said.It can really reveal not just where you are in your tennis game, but in your mind. It's a really good measuring-stick opportunity for him.''


BEATING THE HEAT: The temperature rose into the mid-90s at Flushing Meadows on Tuesday, and that heat, combined with high humidity, prompted the U.S. Open to put its ``extreme weather policy'' into effect as of 1 p.m. for women's singles matches.

That means players are allowed to request a 10-minute break after the second set - and the tournament said at least two matches were interrupted.

Organizers put into motion a few adjustments to help others with the heat, including cutting down ball kids' shifts from 2 hours to 1 1/2 hours, repeatedly reminding fans to stay hydrated and encouraging spectators to move to shaded or air-conditioned areas around the grounds.


PUSHING 40: There are times when Japan's Kimiko Date Krumm stands there in the stifling heat, looks across the net at a woman half her age and thinks, ``What am I doing out here?''

For two hours Tuesday, she answered her own question.

Date Krumm, who turns 40 on Sept. 28, nearly beat 11th-seeded Svetlana Kuznetsova before losing 6-2, 4-6, 6-1 in the first round of the U.S. Open. Had she pulled off the upset, Date Krumm would have been the third-oldest woman to win a U.S. Open match since the Open era began in 1968.

Sometimes, I look across the court and say, 'That looks like my daughter,''' Date Krumm said.But I'm still on my feet.''

Ranked as high as fourth back in 1995, Date Krumm (known as Kimiko Date before she got married) played in the Olympics - the Atlanta Olympics - in 1996, then took more than 10 years off. She announced her comeback in 2008, after being persuaded by her husband to return to the tour.

She slowly played her way back into the top 100 and played the first main-draw Grand Slam match of her comeback at the Australian Open in January.

Her return to the U.S. Open ended up being only a one-match affair, though she had the 25-year-old Kuznetsova in trouble for a while. Date Krumm went old-school, using a backhand slice to move her opponent backward and forward on the court instead of side-to-side.

That was good for one set. Then Date Krumm's left quadriceps started tightening up, Kuznetsova adjusted to the strategy and the match was over.

Everyone's more powerful out there now,'' Date Krumm said.It was very, very difficult to adjust, but I did. Now, it's the recovery that's more difficult to me. I play one day and I'm more tired compared to all the younger players.''


AP National Writer Eddie Pells contributed to this report.