AP National Writer
NEW YORK (AP) - Ryan Harrison might be the future of American tennis.
For now, though, there's work to be done.
The 20-year-old who lives near and sometimes trains with Andy Roddick fell in the second round of the U.S. Open on Friday, 6-2, 6-3, 2-6, 6-2 to 2009 champion Juan Martin del Potro.
"I've got to win one match at this level before I can consistently win at this level," Harrison said. "It's a process and it's going to take, unfortunately, a little more time than I want it to because these guys are all really good."
Now that Roddick is on his way out, 61st-ranked Harrison knows more people are looking to him and the other young Americans to fill the void. In 2010, he was a qualifier ranked in the 200s and became the first American male teenager to beat a top-20 opponent at any Grand Slam tournament since Roddick in 2001.
Since then, Harrison has steadily risen up the rankings but is still in search of his next breakthrough moment. This week's events _ Roddick's retirement, his second-round loss _ didn't change a thing in his mind.
"It's not like I'm going to work harder _ because I already want it and I already work really hard," Harrison said.
Harrison's serve, often clocked above 130 mph, didn't have the same kick in this match, in part because del Potro is one of the best returners in the game and put pressure on the young American. Harrison fell down a break early in the first two sets. He got in only 51 percent of his first serves and finished with five double faults.
"Things tend to snowball whenever you're playing against a guy who makes you play that well," he said.
Winning the third set is certainly something Harrison will use for confidence in the future.
But he's still looking for his first trip past the second round in a Grand Slam. Among those he has drawn over his first 10 Grand Slam appearances are Novak Djokovic, Andy Murray, David Ferrer and Robin Soderling _ all in the top 10 when they played _ along with Gilles Simon and Marin Cilic, who were in the top 30 at the time. All matches that will serve as good learning experiences, though Harrison would like to believe he's ready now.
"I don't feel unready, if that's the right word," he said.
Also falling Friday was 22-year-old Bradley Klahn, the 2010 NCAA champion, who made it through qualifying and came in ranked No. 485.
That left 22-year-old Steve Johnson as the only rising U.S. player to win in Friday's early play at Flushing Meadows. Johnson, the two-time NCAA titlist from USC, is ranked 245th and hasn't been as high-profile on the tour as Harrison. Maybe that will change. He beat Ernests Gulbis 6-7 (3), 7-6 (5), 6-3, 6-4 to make the third round.
Like Harrison, Johnson says Roddick's decision to leave the game doesn't have a huge impact on him.
"I think there are a ton of Americans that are going to come up and do big things," Johnson said. "It shouldn't fall on any one person's shoulders."
(Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)
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