Making it to Center Court at the U.S. Open requires speed, agility, determination, and focus — that’s true for the likes of such top seeds as Andy Roddick and Venus Williams, and just as much so for the ball boys and ball girls who snatch out-of-play balls off the court.

At least, that’s what I learned yesterday when I tried out to be one at the 2007 U.S. Open.

I was number 263 of nearly 400 candidates vying for 75 rookie slots at this year’s Open. In two weeks, the outstanding among us would be invited back for a callback tryout and an interview. Some will go on to work during the Open’s qualifying rounds, and a select few would make it to the final draws.

“Today is the big casting call,” the U.S. Open’s Director of Ballpersons, Tina Taps, told me before the competition started. “It’s the best seat in the house,” she said.

Having arrived early at the USTA Billie Jean King National Tennis Center in Flushing Meadows, Queens, where the Open will take place from August 27 to September 9, I learned about one of the more famous ball people in the Open’s history: In 1971, John McEnroe worked as a ball boy at the U.S. Open at the West Side Tennis Club in Forest Hills, eight years before he won his first Grand Slam title in Flushing Meadows.

Paid ball people must be at least 14 years old and, while most are teenagers, at least one veteran ball boy — if he can be called that — is returning for his 28th consecutive season at the Open. Gary Spitz, 43, an attorney from Long Island, has worked 300 matches, he said.

Not long ago, Mr. Spitz said, Martina Navratilova recognized him as they were passing each other off-court. “You still doing this?” he recalled her asking. “I could say the same thing to you,” he said he told Ms. Navratilova, who won 18 Grand Slam singles titles between 1978–90 and rejoined the professional circuit in 2000.

Yesterday, some experienced ball boys helping with tryouts told me they are aspiring tennis professionals themselves.

“It’s cool to see the professionals and see how they play,” 17-year-old Nathan Hollins, from Queens, said. Suddenly, I felt nervous, surrounded by teenagers, many of whom had been practicing with the hopes of standing behind Roger Federer.

I asked a girl standing next to me, Aishwerya Sharma, 12, how she felt. She said “confident.”

“I hope she will make it,” her mother, Hem Lata, told me. “She’s tall enough and mature.”

Finally, it was my turn. I walked onto the court, where an evaluator named Dorian instructed me to chase the ball, and then get off the court as fast as I could.

When an amateur player helping with tryouts hit a ball into the net, I followed her advice, sprinting toward the ball. Run, scoop, throw. Run, scoop, throw.

It was harder than it looked.

After several minutes, Dorian ushered me off the court and, perhaps foreshadowing my fate as a ball girl, suggested that I work on my throwing. I nodded.

“It’s harder than it looks,” Ms. Taps said, as I exited the tennis complex.