As players at Louis Armstrong Stadium fist-pump in victory or hang their heads in defeat, similar emotions play out nearby, in a ground-floor office.
There, at the U.S. Open's lost-and-found, visitors usually leave with a smile or a grimace.
A fan who lost his iPhone recently came to the office in a panic, said staffer Janet Oconnor, of Westbury.
Oconnor said she used the "Find My Phone" app to track the device, sending employees scurrying in chase as it moved across the grounds. Someone had picked it up and was trying to figure out how to return it.
The next day, prized phone in hand, the fan returned with a dozen doughnuts for the staff.
"He got his iPhone, and he was pleased as Punch," Oconnor said.
Inside the Louis Armstrong office, a large metal chest is stuffed with hundreds of items waiting to be reclaimed by their owners, officials said. There are the expected: cellphones, wallets, hats, umbrellas, cash, car keys -- and lots and lots of sunglasses.
There's also the occasional oddity, such as the older person's hearing aid or the kid's retainer -- possibly abandoned on purpose.
"Eyeglasses and sunglasses are the No. 1 item that gets collected," said Michael Rodriguez, director of security for the three-week tournament in Flushing, Queens.
By six months after the tournament, all unclaimed items are destroyed, except for cash, eyeglasses and cellphones, which are turned over to the U.S. Tennis Association and donated to charity, Rodriguez said.
For the employees who run the lost-and-found, the most precious items aren't always costly. They remember the look of gratitude on a fan's face when they're reunited with a cellphone full of pictures of a new grandchild or an inexpensive fabric friendship bracelet.
"That's why I like to do this job," said Angela Robinson, of East Flatbush, Brooklyn, who has logged and returned lost items to fans for the past five years. "It's very rewarding -- that's why I keep coming back."
Last Saturday, Robinson said, a woman came to the office, tears in her eyes, looking for a canister of tennis balls that she had spent days getting her favorite players to autograph.
"Earlier, we had gotten a thing of three balls, and she said, 'Please look to see if it's autographed,' and I said 'Yes, it is,' " Robinson said. "She was crying, and she said, 'I came all the way from Australia to do this.' "
Not all are winners.
Frank Sholomo, 28, left empty-handed last weekend. "I lost my baseball hat," the tennis fan from Kazakhstan said. He had flown to New York City for a day just to attend the tournament.
"I think it was the lady next to me that stole it," he said with a shrug. "New Yorkers."