On a tropical night in mid-July, Taylor Fritz and Frances Tiafoe, the most touted and perhaps most promising pair of American teens since Pete Sampras and Andre Agassi, played back-to-back first-round matches at the Citi Open in Washington, D.C. How did they get here? Fritz, whose game was meticulously laid out and cultivated in an affluent San Diego suburb, is the son of tennis pros. Tiafoe, the son of African immigrants with no interest or background in the game, was introduced to tennis by happenstance, when his father was hired as the custodian at a tennis academy in suburban D.C. The last wave of American dominance over the sport in the men’s tour, in the 1990s, was by the sons of immigrants, but Fritz is from old money, the great-great-grandson of David May of the May Department Stores Company, founded in 1877 during the Colorado silver rush. Tiafoe’s father survived more than three years in the ­diamond mines of Sierra Leone before emigrating 28 years ago. The case-study comparison is impossible to resist, especially with both set to make splashy entrances at the U.S. Open.

An intriguing question is whose background will give him the edge, particularly since in tennis, the relationship between money and the will to prevail is particularly shaky (whatever you think of the sport’s relationship to white-sweater privilege). Jimmy Connors came from the wrong side of St. Louis, Andre Agassi was the son of a Vegas casino employee, and Dijana and Srdjan Djokovic gambled all on the groundstrokes of their firstborn, Novak. Yet no one has ever stepped on an opponent’s neck as dispassionately as Rafael Nadal, who grew up comfortably in Manacor, or competed as rabidly as John ­McEnroe, who went to high school at Trinity.

But wealth and class aren’t the only things that separate Tiafoe and Fritz — or even the most important things. The ­contrast in their training is the aspect of their backgrounds that most interests the tennis world. Tiafoe came up through institutions, first the Junior Tennis Champions Center and the USTA — the sport’s equivalent of foster care. Fritz received his education in the only way that has ever been shown to work — if not consistently, at least occasionally, the odds on greatness always being long — which is when the curriculum is conceived and overseen by a manic, obsessive, ingenious, and borderline-certifiable tennis parent. Mike Agassi is the patron saint of this cult — he taped a paddle to Andre’s palm when he was strapped in a high chair, then built his backyard court, put 11 ball machines on one side of the net and Andre on the other — but he was preceded by Gloria Connors and followed by Richard Williams. In this respect, Fritz, who enters this week ranked 54th to Tiafoe’s 123rd, is more the model success story: From Jimmy to Andre to Serena and Venus, the best Americans have been shaped and warped at home. Even Sampras, the best male American of all, wasn’t shipped off to an academy early on but entrusted to the inspired autodidact hacker Pete Fischer. Of course, Fritz is no longer at home, having relieved his father of coaching duties shortly before turning pro at the end of last year, then reinforcing the break from his childhood, and parents, by marrying his first serious girlfriend (and fellow 18-year-old) Raquel Pedraza. By contrast, Tiafoe, also 18, remains close with his father, who’d long been known as ­Constant, but several years ago changed his name to Frances Senior, presumably to honor his son.

Read the full “Two Boys Dreamed of Playing Tennis” by Peter de Jonge at nymag.com.