CARLSBAD, Calif. (AP) - Two years ago, Martina Hingis took advantage of a lull in women's tennis. She won 37 consecutive matches, three Grand Slam tournament titles and ascended to the No. 1 ranking at age 16.

With Steffi Graf injured most of 1997 and Lindsay Davenport and sisters Venus and Serena Williams not yet developed into serious challengers, Hingis easily ruled the courts.

``I had an open road,'' she said. ``I don't think I understood really what was going there at that time. I kept winning, but I didn't really appreciate it because it just was so easy.''

It's not anymore.

Hingis heads into the U.S. Open later this month wondering if she can still beat the top players. She admits to being nervous, a feeling that first consumed her a year ago.

``I know I've won five Grand Slams, I shouldn't be nervous about that, but still, if you can do it again, if you can beat those players you used to beat,'' she said.

Even though she's ranked second, Hingis says, ``I miss being one of the best players in the world. I'm used to that.''

The 18-year-old no longer dominates the way she did in 1997. She's been replaced at No. 1 by Davenport, who beat Hingis in last year's U.S. Open final.

And the once-cocky Hingis has lost crowd support this year. A fan shouted, ``Go home, Martina'' during one of her matches at the TIG Classic this week.

She began the year by defending her Australian Open title, but she ran into controversy Down Under when she reportedly described her opponent in the final, Amelie Mauresmo, as ``half a man.''

In Paris, Hingis lost to Graf in the final and repeatedly battled with the umpire and linesmen. Hingis was jeered by the crowd for serving underhand, and only returned for the awards ceremony at the urging of her mother.

She hit rock bottom at Wimbledon, losing in the first round to 16-year-old qualifier Jelena Dokic. For the first time, she was at a tournament without her mother and coach Melanie Molitor, who has since returned to her side.

``It's much tougher,'' Hingis said. ``I would love to have another year like '97.''

As Hingis ponders her vulnerability, so do other players.

``It's going to be very interesting to see how she reacts to the troubles she's had,'' said former No. 1 Aranxta Sanchez-Vicario. ``I guess that's the test; to see how one reacts when they are down. Only time will tell.''

Hingis admits she was complacent in '97. She won so often and easily that she never had to think much on the court.

``Before, everything was so natural, I just came out there and I had the feel and I just played my game,'' she said. ``In practice, I don't always have that confidence like I used to have a half-year ago. My body has changed and I have to work more.''

Hingis took a month off after her Wimbledon disaster. She practiced and worked on her strength by lifting weights. And she thought long and hard about being the best.

``You want that again because you're used to it and you know it is possible, so you want to go back out there and beat everybody,'' she said.

At times, Hingis believes fans forget she's still only 18, a teen-ager struggling to regain her place in the new world order of women's tennis. But even though she's heard more boos this year than at any time in her career, Hingis still craves the attention.

``If there wouldn't be anybody watching me, I wouldn't like it,'' she said.