Alright boomer
I'm only relaying what was reported in NY Mag:
It turns out that for the first half-dozen years of his tennis life, at least, Tiafoe was on his own. He got up, grabbed whatever racquet he felt like borrowing that morning from the pro shop, and wandered the grounds. He stood on the sidelines as other kids got lessons. He watched matches on the TV in the lounge, which was always set to the Tennis Channel, and tried out what he observed on the concrete wall just outside the gym, where, according to teachers and former students, Tiafoe routinely spent six to eight hours rallying with himself, devising an endless series of games and drills and challenges to stave off boredom. In the evening, when the paying and scholarship students went home, he set up camp on an empty court and hit serves, and in between, according to Frank Salazar, who coaches the academy’s elite players, “he would play anyone with a pulse.”
“In the beginning stages,” says Tiafoe, “I was just watching. I learned a lot from mimicking things and seeing little things. The next thing you know, I started to understand the game pretty well. One thing leads to another. I really studied a lot … watched a lot of film. Obviously, I didn’t have coaches or anything like that.”
Early profiles describe the young Tiafoe as a sponge, quietly taking in everything he sees and hears, absorbing the details and nuances of the game 24/7. It’s a good thing, because he wasn’t getting much formal instruction from anyone else. According to 21-year-old Luca Corinteli, also a product of the JTCC and now a UVA senior who plans to turn pro next year, the reason Tiafoe’s game still looks other than textbook is that in the critical early stages of his development, he was essentially self-taught, and those lessons were imprinted by hammering countless balls against a wall.