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Coco Gauff will never forget the utter elation she felt last September when her backhand winner flew by Aryna Sabalenka at the U.S. Open final to give her, at 19 years old, her first Grand Slam championship. “It was like a drug,” Gauff says. “I’ve never felt anything like that.” And this is coming from a person who has bungee jumped off Sky Tower, New Zealand’s tallest building—twice.

Gauff wants to feel that championship high again. “That’s the motivation that drives me,” she says. “I’m sure the ‘Face of Tennis’ and glitz and glam will come along with that. But I don’t really care about any of that. I really just care about how many of those major trophies I can get in my house.”

The phenom fell just short in January, when she lost in the semis of the Australian Open. But Gauff’s triumphs have already fulfilled the promise she first showed at 15 in 2019, when she advanced to the fourth round of Wimbledon. Some pundits expected more majors from her sooner, but Gauff progressed at her own pace. And now, according to Sportico, she’s the world’s highest-paid female athlete. The more than $22 million Gauff earned in 2023, mostly from endorsements, is a point of pride.

“Being a Black woman, in a sport that isn’t as diverse as others are, it definitely means a lot to me,” she says.

Having an activist in the family—Gauff’s grandmother was the first Black student at her Delray Beach, Fla., high school in 1961—has shaped her perspective. In the days following the murder of George Floyd in 2020, Gauff posted about the injustice on social media and spoke at a protest. “It was to the point where I was crying about it, because I felt like I had to say something,” she says. She addressed the crowd in Delray Beach: “If you are choosing silence, you’re choosing the side of the oppressor.”

Gauff turns 20 in March. “It’s crazy to think that I’m not going to be a teenager anymore,” she says. “So much of my career, people have called me the teenaged this, teenaged that.” But she knows she’s still early in her journey. “At first, I was scared to grow up,” she admits. “But now I’m embracing adulthood. There’s always going to be change needed in this world. I hope I can play a small part.”

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Write to Sean Gregory at sean.gregory@time.com.