John Isner, the 6-foot-9-inch former University of Georgia standout, lopes around the tennis court. At times he looks lost, as if orbiting a planet far, far away. His steps lack the bounce you see in most tennis players. A quick glance at his baby face, and you might wonder if he just woke up a few minutes before playing a casual game, not his first ever match at the U.S. Open.

Yesterday, Isner won and did so, well, casually and calmly. Just like he did in Washington, D.C., this summer, when he reached the final after winning a series of three-set matches that most rookies wouldn’t win. Not much tension. No worries. And not a single game lost on his remarkable serve, which produced 34 aces and frustrated his opponent, Jarkko Nieminen, the no. 26 seed, to no end. The Finn, once a junior champion at this tournament, bounced his racket in disgust. He hit one service return so late that the ball ricocheted off the chair where umpire Eva Asderaki was seated. She laughed (a bit nervously), and Nieminen pointed the butt of his racket at her and pretended to shoot. Nieminen faced only one break point himself, and the 22-year-old Isner, a sleeping giant, opened his eyes long enough to slap a backhand return winner down the line on his way to a 6–7(4), 7–6(4), 7–6(5), 6–4 victory. “It was the most difficult serve I have ever returned,” Nieminen said. “It’s the bounce because he is so tall.”

Nieminen said Isner’s second serve, which usually breaks the 110 mph barrier and often reaches 120 mph (not much slower than Isner’s 140 mph first serve), is even better, again because of the bounce. “The second serve is his best shot,” Nieminen said.

Isner, who arrived at his press conference with his right arm and shoulder wrapped in ice (just a precaution, he said), is a rare breed in men’s tennis: He finished four years of college in a time when most top prospects don’t even think about attending college at all. He said that compared to the pressures of playing team tennis in college, the pro game has been relaxing.

“That’s probably the last time I was nervous,” Isner said, recalling Georgia’s championship run. “Now I kind of expect to go out there and win and compete, give whoever I’m playing a match.”

Isner was the second young American to win his first match at the U.S. Open yesterday, following Donald Young, who carried his recent momentum from New Haven, Conn., where he won his first professional match, into his first-round contest against Chris Guccione, a hard-serving lefty from Australia, 6–7(2), 6–3, 6–2, 6–3. Guccione, who is 6 feet 7 inches, is known as something of a serving machine, but Young, he of the formerly underwhelming but now rapidly improving serve, matched Guccione with nine aces. He also hit the most spectacular shot of the afternoon, when he leapt to retrieve a Guccione overhead and swatted it back with an overhead of his own. A stunned Guccione stiffened up and volleyed Young’s reply into the net.

“It’s awesome,” Young said. “It feels great to have won the match.”

The 18-year-old Young’s next opponent, Richard Gasquet, may be a veteran with five years on the tour, but he’s only three years older than Young, and knows a lot about carrying the expectations of a nation on his shoulders. Gasquet has been the future of French tennis since he was a child, and had largely disappointed until recently, when he defeated Andy Roddick in the quarterfinals of Wimbledon. Gasquet is one of the finest shot makers on tour, and he and Young could put on quite a show for a second round match. Two other Americans, Scoville Jenkins and Jesse Levine, had less successful outings. Jenkins lost in straight sets to Roger Federer — no shame in that — 6–3, 6–2, 6–4, while Levine, the third ranked player in the NCAA this year as a freshman, lost to no. 4 Nikolay Davydenko 6–4, 6–0, 6–1.

Levine, who recently decided that he won’t return to the University of Florida this year, knows a thing or two about Federer. Last month, he received a call from an agent at IMG, asking if Levine would fly to Dubai to practice with Federer.

“I was like, yeah very funny, who is this,” Levine said. It wasn’t a prank, however, and Levine decided to pass up two tournaments to hit with the world no. 1 for 10 days. He and several other players took part in three- or four-hour practice sessions, sometimes twice a day. They couldn’t begin until 5:00 p.m. because of the 130 degree temperatures. He was amazed, he said, by how hard Federer works.

After a great college season, a trip to a five-star hotel in Dubai courtesy of the world’s best player, and a wild card into the U.S. Open, Levine will now leave the spotlight for some hard work of his own. His next stop? New Orleans, for a Challenger tournament that begins on September 10.

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Marcos Baghdatis’s slump continues. The entertaining Cypriot, perhaps best remembered by New Yorkers for his riveting match against Andre Agassi last year, lost in the first round yesterday to Max Mirnyi in four sets.

Mr. Perrotta is a senior editor at Tennis magazine. He can be reached at tperrotta@nysun.com.