From their umbrella-topped lifeguard chairs, umpires in professional tennis only refer to the players by their last names, a formality that sanitizes the affection from their professional relationship. But tennis fans aren’t beholden to the custom. They've graduated to a first-name basis with their favorites, like Roger Federer. In the beginning he was Federer, then Fed as he accumulated major titles and goodwill. Now almost universally he’s just Roger, on an intimate basis with a tennis world bracing for the vacuum that will be left by his impending retirement. Nadal's appellation, on the other hand, is more fluid, like his ropey forehand—Rafa, Rafael, and Nadal all at once—and not because feelings change about him but because the variety of his beautiful game is appreciated by tennis fans the way certain cultures have multiple names for snow. That Djokovic isn’t called Novak tells you something about how fans feel about him, despite his status as arguably the sport’s most successful champion.We’re in the waning reign of the big three of Federer, Nadal, and Djokovic. They will soon be gone, their dominance of the sport subverted by the so-called next gen players, the young, under 25-year-olds on the ATP tour: Thiem, Medvedev, Zverev, Tsitsipas, Rublev, Berrettini, a few others. On Monday at the US Open, with Federer and Nadal both out with injuries, but with Djokovic still supremely confident in his status as the favorite (on a scale of 1 to 10, he said he believed he was an 11), some 39,000 fans made their way to Queens, New York, to see if any of the new crop of players might be first-name-worthy.The United States Tennis Association did not make it easy for us. On Monday morning it was nothing but mayhem as thousands tried to enter the gates of the National Tennis Center at Flushing Meadows Corona Park. Veteran ticket holders said they’d never seen the Open so poorly managed. For close to two hours, under a brutal sun, there wasn’t a staffer in sight outside the gates. The intense heat led to people vomiting in trash cans while others held their spots in line. Yet fans persisted for the first day session of the two-week tournament. They'd already waited too long. Last year's event was held with no fans in attendance.Getting close to the players is one of the thrills of the US Open. The jumble of side courts give the feeling of watching a high school tennis match from court-side bleachers, except the players here are some of the tour’s best. Over on court 5 on Monday morning, the tournament’s 11th seed, the Argentine Diego Schwartzman, set to work against Ričardas Berankis, an unseeded Lithuanian.At 29 years old, Schwartzman, the second-highest ranked Jewish tennis player in the world at No. 14 (the Canadian Denis Shapovalov, No. 10, has a Jewish mother), has been on tour too long to be branded next gen. He’s Diego to his fans, who shouted vámonos vámonos and slapped their Argentine soccer jerseys as he smoothly demolished Berankis in the first set, 7-5.At the start of the second set, a gaggle of chirping boys huddled in the corner of the stands, holding giant yellow tennis balls and sharpies in case Schwartzman decided to start signing autographs midgame. As he came for his towel, which the players now have to fetch themselves, as they always should have, Schwartzman had to establish some boundaries.“Come on, guys, guys, some space, please,” he said, but not without a friendly familiarity, and one could see the boys' heads swelling from the personal attention. Schwartzman is an atypically short player on the tour, as is Berankis (neither appear in person to reasonably represent their official heights, which are listed respectively at 5’7" and 5’9"), and their defensive games—getting everything back to grind opponents down—are similar. Both lack the major power arsenal of the larger and stronger players on tour, though Schwartzman sits higher on the tennis pecking order thanks to his superior speed.Schwartzman’s appeal resides in part in his tenacity; he simply keeps sending the ball back over the net like a human backboard, flummoxing opponents the way diminutive American Jewish tennis ace Harold Solomon once did. Solomon was officially listed at 5’6" and ranked as high as No. 5 in the world in 1980. In 1977 Solomon was a semifinalist at the US Open, which was then held in Forest Hills, Queens, where he lost to eventual champion Guillermo Vilas, the idol of Argentine tennis pros and father of what is still the world’s most iconic tennis sneaker.Schwartzman’s game has been forged from the supreme Nadal mold. With his big, looping top-spin forehand, Schwartzman does not have the Spaniard’s raw strength to produce the same pace. To replicate Nadal’s forehand, Schwartzman must bend so low that his knee hovers close to the court, so he can get under the ball and sweep it with enough spin. There is, in other words, a great deal of visible effort in Schwartzman’s game, a palpable intensity with which he tries to close the gap with Nadal’s more innate artistry.The Schwartzman forehand was in fine form in the third set against Berankis, frustrating the Lithuanian to the point that he smashed his racket against the back wall. Schwartzman chipped away at Berankis’ 40-15 lead during the seventh game, which left Berankis so rattled he double-faulted the break away, and Schwartzman sailed smoothly to a 6-3 and decisive third-set victory. Though Schwartzman was unceremoniously bounced out of the Open last year in the opening round after blowing a two-set lead, he has reached the quarterfinals twice, most recently in 2019, when Nadal avenged a recent loss to his mentee in straight sets and sailed through to the semis.With Nadal and Federer out with injuries this year, it might be the most favorable draw the Argentine has yet seen. If he can keep his unforced errors down (a too-high 31 to his 23 winners against Berankis), and continues to convert breakpoints (he won five of nine against Berankis), Diego won’t run up against a high-seeded next gen player until he likely encounters Daniil Medvedev in the quarterfinals. And if he manages to make it that far, it’s a sure bet that there will be shouts of Diego all throughout the stadium, as the spirits of Solomon, Vilas, and Nadal hover somewhere nearby.