Bobby Reynolds did not act like a man about to be fed to a lion. As he practiced beneath the hot afternoon sun on Saturday, his shirt off, his baseball cap soaked, Reynolds laughed and razzed his hitting partner, Brian Baker. They played a set, then drilled dozens of forehands and backhands. Between shots, Reynolds routinely walked over to the small row of bleachers alongside Court 15, where a group of enthralled children jumped up to smack his hand with high fives.

Today, Reynolds, a 23-year-old from Marietta, Ga., begins his second U.S. Open, and for the first time he will play in front of thousands gathered inside the cavernous Arthur Ashe Stadium. The lion? Spanish teenage sensation Rafael Nadal, the no. 2 player in the world and the second seed.

“You hate to draw the no. 2 seed,” Reynolds said after his 45-minute practice session. “But there are always upsets.”

As far apart as Reynolds and the 19-year-old Nadal are in terms of talent and rank, both have had banner seasons of a kind.

Nadal, who turned pro at 15 in the fall of 2001, has carved up the tour this year with wicked passing shots and a left-handed, topspin forehand that bounces like no other. So far, he has posted a 65-9 record and won nine titles, including the French Open. He defeated Roger Federer in Paris and nearly beat him a second time on hard courts in March; this summer, he won his first hard-court title by beating Andre Agassi at the Rogers Masters in Montreal.

“At a young age like this, it is extraordinary, really,” Federer said of Nadal over the weekend. “I’m a big fan of his game. It’s something I haven’t seen in – basically never.”

Reynolds, who was the top collegiate player in the country in 2003 as a junior at Vanderbilt University, may measure success on a different scale, but he has had plenty to be pleased about this year.

He made a name for himself at the Australian Open, booking a flight there despite no guarantee that he would even be allowed to play the qualifying tournament. When more than a dozen higher-ranked players dropped out, Reynolds was given his shot. He not only qualified, but won two rounds, finally losing to (whom else?) Nadal.

Since then, Reynolds has reached the semifinals of second-tier tournaments in Mexico City and California, and the quarterfinals of the Legg Mason Tennis Classic in Washington, D.C., where he defeated two players inside the top 100. His ranking is now at an all-time high of 129.

“I got a late start,” said Reynolds, who left Vanderbilt after three years and plans to complete his degree sometime in the future. “I feel like my game is growing steadily, not in leaps yet.”

For those who improve steadily – rather than exponentially, like Nadal – the world of professional tennis is far different from the one we imagine and see on television.

Nadal has earned $3.3 million in prize money this season; Reynolds has earned $160,000 in his career. Players the caliber of Nadal can pick and choose their tournaments and hop the globe in comfort, their friends and families in tow.

Reynolds, meanwhile, travels less luxuriously with the 20-year-old Baker, who graduated first in his high school class before turning pro in 2003, and Amer Delic, a 23-year-old who was the no. 2 college player in 2003 (behind Reynolds) as well as the NCAA singles tournament champion. (Vanderbilt and Illinois, Delic’s team, met in the team championship match that year; Reynolds won their contest, but Illinois won 4-3 to cap a 32-0 season.) The three share a coach, Ricardo Acuna.

While Reynolds and Baker were given wild cards into this year’s U.S. Open draw, Delic was forced to play qualifiers and lost.

After his workout on Saturday, Reynolds was scheduled to drive to New Haven, Conn., where he played in the doubles final of the Pilot Pen yesterday with Rajeev Ram (they lost 6-4, 6-3). He had hoped to drive back to Flushing for his first practice session inside Arthur Ashe, at around 5 p.m. or 6 p.m., but the doubles match finished late, owing to rain delays, and likely interfered with his session.

Center court or not, preparing for Nadal is no easy task. In their last meeting, Reynolds won just five games in three sets. At the end of their workout on Saturday, Acuna, standing at the net, began feeding Reynolds balls with exaggerated spin, trying to imitate what Reynolds will receive from Nadal.

“But it’s going to be up here, though,” Reynolds said, jumping up and swinging at an imaginary ball about a foot over his head.

“He’s unbelievably fast, and he’s so steady,” Reynolds said of Nadal. “I don’t know if I can stand back and grind with him. I feel like I have to serve well.”

Otherwise, he will rely on his speed and persistence. Reynolds’s frame is small – 6-foot and 170 pounds – compared to the hulking Nadal, who is only an inch taller but nearly 20 pounds heavier. Reynolds prefers to hit forehands, though his backhand was impressive enough on Saturday to please Acuna and several passers-by, one of whom asked a reporter, “Who is that guy?”

Reynolds does not seem to mind the anonymity, though a win today – a shocker, indeed – would certainly garner plenty of attention.

But even if he loses, just having a chance to play on center stage will be enough this year.

“It’s a pretty big stadium,” he said, laughing as he glanced up at Ashe, towering in the background. “It will be an experience I never forget.”

Open for Business as Rain Looms

And so it begins. After a weekend of practicing, stretching, running, and interviews, 256 of the world’s best tennis players today start down the road to a U.S. Open title.

The day session is highlighted by Serena and Venus Williams, who play on Arthur Ashe, along with Rafael Nadal. Meanwhile, Kim Clijsters, who said yesterday that she plans to retire in two years at the age of 24, begins her best chance at a Grand Slam title inside Louis Armstrong Stadium (watch her while you can).

Want a competitive match for your hard-earned dollar? Stop by the Grandstand, where 20-year-old American Brian Baker challenges former French Open champion Gaston Gaudio, seeded no. 9. Prefer to see the future of women’s ten nis? Find a seat at Court 7, where 16-year-old Nicole Vaidisova of the Czech Republic and 17-year-old Ana Ivanovic of Serbia and Montenegro face off to begin the day.

As for the night session, top-seed Maria Sharapova, whose no. 1 ranking lasted all of a week (it now belongs to Lindsay Davenport), kicks things off with a difficult match against Eleni Daniilidou, a powerful player from Greece. Two-time champion Andre Agassi, playing his 20th U.S. Open, follows.

Of course, all this is subject to change, now that the rain, having ignored New York City the entire summer, has decided to settle in for an extended stay. By Thursday, all the stars may be on court at once.