“Every decision that they made, my tennis was behind it. My dad was like, ‘Should I take this job if I have to be a little farther away?’” Noah recalls. “If I negatively affected them early, I hope to make up for it. I make fun of him. I say, ‘Dad, you only had me so you could have a retirement fund.’”

By the time he was a toddler, Noah was swinging at a tennis ball hanging on an elastic band from the family’s living room archway in Merrick, N.Y. In his bio on the International Tennis Federation website, it lists: “Age Started Tennis — 1.”

“We had our kids on the court from the time they were in diapers,” Melanie says.

Laminated mock-ups turned the dinner table into a mini court for discussing strategy. Even his bar mitzvah had a “Noah’s Grand Slam” theme.

The intense focus on tennis didn’t do much for Eric’s banking career. He bounced from NatWest to North Fork Bank to a six-month stint with Citibank. “I left NatWest on Wall Street for no other reason than to be with my kids, to teach them tennis in the morning before work,” Eric says. “I got in late every morning [at North Fork] because I was out teaching Noah at 5 a.m.”

As for Citibank: “They’re a business, I don’t blame them for it. They expect people to be at their desk, and I had other priorities.”

At 7, Noah was beating kids almost twice his age in tournaments, so the Rubins turned to Kleger—who was then executive director of tennis for Sportime—for support. Eric and Noah still scraped ice off courts in Newbridge Road Park on wintry Long Island mornings to play before school.

After Noah won a regional tourney as a 10-year-old, other parents crowded around him asking what he ate before matches and how he warmed up. He was a 2010 finalist at the prestigious Les Petits As 14-and-under tournament in Tarbes, France, whose past winners have included Rafael Nadal and Michael Chang.

By then, Noah was receiving free rackets from Head and clothing and shoes from Adidas. Sportime and the McEnroe Academy started covering the cost of his tennis lessons, as well as online classes that ran about $7,000 a year, after he left high school before 10th grade. The Rubins paid about $10,000 for tutors in the 18 months leading up to college, using part of Eric’s buyout from North Fork.

Although tennis didn’t cause the breakup of the Rubins’ marriage, it led to constant tension over Noah’s future and how much he should focus on the sport. Melanie says the divorce cost her about $100,000, plus as much as $25,000 in post-divorce court proceedings in which “tennis was always the driving factor.” Eric says his costs for the divorce and subsequent legal actions were in the six-figure range.