NEW YORK — She sat there in shock. Then, the tears started falling.

Believe it or not, 17-year-old Melanie Oudin is the toast of the town at the U.S. Open.

Gritting her way through a shaky third set, the 70th-ranked player from Marietta, Ga., pulled off her second upset of the Open on Saturday, defeating a more-seasoned, more-famous, more-moneyed opponent — 29th-seeded Maria Sharapova, 3-6, 6-4, 7-5.

"I don't even know what to say right now," Oudin said, choking back tears in her postmatch interview in Arthur Ashe Stadium. "Thank you so much for cheering for me."

Sharapova, who has won this tournament once, usually gets those cheers. But on this cloudless day in Queens, the fans were rooting for a new potential queen — the one who stamped the word "Believe" on her shoes, but probably didn't see this coming so soon.

"My goal was to make the top 50," she said. "But if I keep playing like this, who knows? Hopefully, I can get as high as anything."

She added this upset to one over No. 4 Elena Dementieva in the second round and a win over former No. 1 Jelena Jankovic this year at Wimbledon.

Her confidence is growing as quickly as her resume, and suddenly, it does seem like anything is possible.