New York: Andy Roddick, the 2003 champion, reached the third round of the US Open by beating American teenager Jack Sock 6-3, 6-3, 6-4 on Friday.

Sock, 18, earned a wild card into the US Open each of the last two years by winning the boys' national championship. Against Roddick, he showed off some of the skills that make some think he could be the country's next star tennis player. Sock hit 10 of the match's first 11 winners.

"He came out hot. He came out full of energy, almost like he was 18 years old," Roddick said during his on-court interview afterward, drawing laughs from the crowd at Arthur Ashe Stadium.

But Roddick's experience paid off at the key moments, and he converted 5 of 5 break points. Sock made good on 1 of 7.

The 21st-seeded Roddick's ranking dropped out of the top 20 this season for the first time in a decade.

"Three years ago, four years ago, I started hearing about this kid from Nebraska," said Roddick, who like Sock was born in that state. "He was gangly, hit the ball hard. ... It all sounded too familiar. I'm really excited about the future of American tennis. It is bright."

Sock whiffed on his first six break chances, including four in the fourth game of the match, which Roddick ended with one of his 11 aces.

"I've been that kid out here at 18 years old, playing way too fast," Roddick said.

In the very next game, Roddick broke to go ahead 3-2 when Sock netted a volley at the end of a 13-stroke exchange.

"Changed the whole dynamic of the match," Roddick said.

Struggling with various injuries, former No. 1 Roddick is having a tough season, and his ranking dropped outside the top 20 for the first time in a decade. Most recently, he was sidelined by a torn abdominal muscle that made him unsure of whether he'd even be able to enter the U.S. Open.

Now he's into the third round for the ninth time in 12 appearances at the year's last Grand Slam tournament.