NEW YORK -- Dustin Tankersley remembers this clearly. It was 2013 and he was a sleep-deprived US Open racket stringer, standing 18-hour days for nearly three weeks straight. It was late and most of the other stringers had left for the night, but he was one of a pair required to stay until the last match of the day was completed.
Rafael Nadal, who had just completed his match, unexpectedly walked into the stringing room.
"Thanks guys," he said. "I'll see you tomorrow."
The few stringers left in the shop were surprised and grateful that their work had been noticed and appreciated.
"He walks out of his way to come into the room and say thanks," Tankersley said. "And you don't get that very often."
Players come in with six to eight rackets, and want synthetic strings such as Luxilon or natural such as cow gut, loose or tight, strung first thing in the morning or just before a match. When things go right, the stringers rarely hear about it. But when they go wrong, frustrations can be as high as the stakes at the US Open.
Wilson, the equipment manufacturer, runs the operation for the US Open and a few other tournaments. The 18 stringers who work for the US Open qualifying tournament and main draw go through a surprisingly rigorous selection process. Every year since 2009, Tankersley has flown from Dallas to New York, where he strings rackets to ridiculous specificity, some days from 7 a.m. until the last ball is struck.
They may not see their names in lights or be introduced to a standing ovation at Arthur Ashe Stadium, but Wilson's Ron Rocchi said the stringers here are every bit the professionals as the players they quietly work for. They stand in rows spinning the frames as they work, focused down as tennis luminaries and champions walk by the glass window in front of them.
"We average 18 minutes," Rocchi said. "We could string faster, but we need quality and consistency."
On Monday, the group completed 514 rackets, a record for the tournament. And it doesn't matter if it's Andy Murray or one of the juniors playing on an outer court; each player gets the same attention and accommodation.
"Anyone can request anything, and we'll always say yes," Rocchi said.
There is an exception -- and that's when a player needs a racket restrung in the middle of a match. So let's say John Isner is playing on the Grandstand and breaks strings on three rackets. He might have a ball boy or girl run a racket straight to the desk of the stringing room. Tankersley or longtime stringer Yat Kong would then assign it to the next available worker, and 20 minutes later the racket would be back on the court.
"It's a factory," said Simona Halep, the No. 5 seed in the women's field. "They are very fast. They are very good. All the rackets are made in time and very well done."
With stringers from a variety of countries, including Japan and Argentina, players can explain their requirements in their own language.
Many of the stringers, such as Joe Heydt of Omaha, Nebraska, grew up playing and stringing their own rackets. Heydt was 17 when he broke a string, and then another, and then went to his local tennis store to figure out how a racket worked. The owner hired him to string in the shop. Eventually, Heydt ended up opening a branch of Racquet Corner in Omaha.
Each stringer has his or her own machine -- the Formula One racers of racket stringing, Rocchi said -- that has digitally stored preferences for height and tilt. Those specifications might not make a big difference when stringing one or two rackets, but given the volume, it's huge.
"It's a professional machine, and it's made for people who are going to be stringing all day long," Heydt said.
By the end of a tournament, Heydt says his fingers are calloused and feel like hard M&Ms from forcing strings into alignment after the stringing is complete. He has a metal tool to help, but it's not as effective as feeling for himself where the cross-strings need to sit on the mains.
Both Heydt and Tankersley say that the cache of being a US Open stringer is good for business. But that isn't the pull that keeps them coming back. It's not the travel, either. Heydt has been to the Australian Open seven times but spends most of his days at his machine or sleeping.
Instead, it's a chance to be on the grounds at a Grand Slam, to see the players and, on a night before he won the US Open, have Nadal come in and say thanks.
"Every job has a pinnacle," Heydt said, "and this is the pinnacle of racket stringing."