Li Na of China reacts to her loss against Simona Halep of Romania during Day Two of the 2011 US Open at the USTA Billie Jean King National Tennis Center on August 30, 2011 in the Flushing neighborhood of the Queens borough of New York City.

French Open champion Li Na suffered a shocking early exit in the first round of the U.S. Open after losing to 53rd-ranked teenager Simona Halep on Tuesday.

Li, seeded sixth, lost 6-2, 7-5 to Romania's Halep, suffering first-round exit for the second time in a row.

Li admitted she has been struggling since the French Open win.

"For me, I really want to do well after Roland Garros. But it's not easy to do. Always easy to say, but always lose early. Now I even lose all the confidence on the court," said Li, who since Roland Garros had not won consecutive matches until last week when she reached the semifinals at New Haven.

Li has stumbled badly in the Paris aftermath, losing confidence with each early-round setback.

"Before the match, I talked to my coach. I say, I didn't have good timing to hit the ball. He tell me everything is perfect, everything is fantastic.

"I say, yes, everything is fantastic, but I always lose first round. I mean, this is not fantastic. I think we need to change something. I think maybe the team or coach just try to give me confidence, but I don't think I get."

Li could not rely on the rest of her game against Halep, landing only 61 percent of her first serves and failing to fire an ace. She had only 22 winners in the match.

The second round at Flushing Meadows will be without all three of this year's major champions. Australian Open winner Kim Clijsters withdrew because of injury, while Wimbledon champ Petra Kvitova lost on Monday.

It's the first time that's happened since 1971.

The 19-year-old Halep beat a top-10 player for the first time in four tries. The Romanian was playing in her second U.S. Open match.