Juan Martin del Potro’s friends cheer from a suite box at the U.S. Open. (Kena Betancur/AFP/Getty Images)

Here’s the thing about those boys from Juan Martin del Potro’s hometown of Tandil, Argentina — you know the ones — who every night fill a different suite, drink beer, provide laughs and make Arthur Ashe Stadium sound like a soccer pitch: It’s possible we have been underestimating their value.

Perhaps it’s because del Potro was sandbagging. He said one day that he flew a group of his closest childhood friends to the U.S. Open so they could finally understand his unique lifestyle. When asked a separate time, he simply responded, “They’re my friends,” and stared blankly because that was explanation enough.

But when del Potro, 29, was asked Friday night after reaching the second Grand Slam final of his career nine years after reaching the first, the No. 3 seed paid his friends their proper due.

Between del Potro’s five-set victory over Roger Federer to claim the 2009 U.S. Open title and Sunday’s final against Novak Djokovic, the 6-foot-6 Argentine underwent four wrist surgeries, including three on his left wrist that made it difficult to hit a two-handed backhand properly.

So prolonged were del Potro’s struggles that he fell into a depression. He was home in Tandil passing time watching “Breaking Bad” and “The Simpsons” on Netflix. In 2015, he contemplated quitting.


Del Potro, 29, is in his second U.S. Open final nine years after reaching his first. (Adam Hunger/Assocaited Press)

“Well, you see the friends who came to watch me? They are very important for me to be in this stage because they were behind me in those years, trying to keep my mind in a positive way, [telling me] to never give up during my wrist problems. I didn’t know if I will be a tennis player again or not,” del Potro said Friday.

“But I’m here. I’m excited to keep surprising the tennis world, as I did with myself. You never know what could happen in the future. So I’m happy just to be a tennis player again.”

Del Potro’s return to the top of the sport — he is ranked third in the world after Rafael Nadal and Roger Federer — is nearly unimaginable for a man who missed 14 Grand Slams in the past nine years.

His talent was never in doubt. Entering the U.S. Open, del Potro, Marin Cilic and Stan Wawrinka are the only players outside of tennis’s “Big Four” who have won any of the 54 Grand Slam tournaments contested since the 2005 Australian Open.

His record against No. 6 seed Djokovic is 4-14, with the Serb winning six of their past seven encounters. But del Potro owns one of the most significant wins of the entire series, a victory in the opening round of the 2016 Olympic Games in Rio de Janeiro.

“He was always a top five player in the eyes, I think, of everyone. Even when he dropped his ranking and started to, you know, work his way up. . . . It was just a matter of time,” Djokovic said Friday.

“I saw today before the match against Nadal a stat that he’s the player that made most wins against No. 1s in the world. That shows the quality that he has, especially in the big matches. He’s a big-time player. He’s a big-match player. He’s a Grand Slam winner. He’s playing the tennis of his life, without a doubt, in the last 15 months.”

Djokovic knows how it feels to make a return like that.

The 31-year-old has a comeback story of his own, though it is far less prolonged than del Potro’s. A right elbow injury bothered him on and off for two seasons before he finally decided to have surgery in February. Djokovic regained the physical strength and confidence necessary to play at tennis’s top level and won Wimbledon last month, ousting Kevin Anderson in the final.

On Sunday, he will face his biggest test at this U.S. Open. He hasn’t yet played an opponent with a forehand or a serve as big as del Potro’s, and the crowd probably will be against him. Del Potro’s boys will make sure of that.

Aside from his friends, the fans at Billie Jean King National Tennis Center fell in love with del Potro when he was a lanky 20-year-old. He will turn 30 later this month, and the affection he feels from the crowd and fellow players on tour has not waned.

“I mean, he’s a gentle giant,” Djokovic said. “He really is. He’s very tall, has a big game, but at the same time he nurtures the right values in life. He cares about his family. He cares about his friends. He respects everyone. He fights every match from the first to the last point. I think people can relate to that and appreciate what he brings to the tennis.”

While del Potro has the crowd, Djokovic is still the favorite to win, having won 13 straight sets entering his eighth U.S. Open final. With a win he would tie Pete Sampras with 14 Grand Slam titles.

But the Argentine has been the underdog before. Against Federer in 2009, he was going for broke. Nine years later, del Potro has a new appreciation for reaching another U.S. Open final.

“I didn’t expect to get this kind of emotions playing tennis again. Reaching finals, winning titles, having my highest ranking ever in this moment, everything is almost perfect,” del Potro said, smiling. “But I don’t know. When I played Roger nine years ago, he was the favorite to win as well. I will try to make the surprise again.”