At Indian Wells, Naomi Osaka looked like she could beat any tennis player in the world. She’d entered the tournament unseeded, having never won a WTA title before. But in the heat of the desert, she proceeded—efficiently and almost cruelly—to dismantle opponents at their own game. First, the 20-year-old stunned former no. 1 player Maria Sharapova in straight sets with her precise and powerful serve. (Sharapova would part ways with her coach after that match.) Later, she took out Karolína Plíšková, another former no. 1, with a unrelenting series of crushing forehands from the baseline.

And when defeating former no. 1’s wasn’t enough, she matched up against the current one, Simona Halep, and throttled her so badly that Halep didn’t win a single game in the second set. Her finals match against Daria Kasatkina was nearly as effortless. The victory speech she gave after that? A different kind of effortless.

“Hello, hi, I am—okay never mind,” she started, before meandering through a series of thank you’s in a seemingly random order, giggling throughout. After a couple minutes, she closed by saying, “This is probably gonna be the worst acceptance speech of all time.”

On the court, Osaka appeared confident and fearless. But as soon as she was off of it, she returned to being a soft-spoken teen with a penchant for nerdy interests. At a press conference after the finals match, Naomi Osaka described the feeling of winning her first title the way any champion would: in reference to a meme. “Towards the end I didn’t know that I won the match point,” she said. “So then I was like Caveman SpongeBob.”

Four days later, in the first round of the Miami Open, Osaka faced her childhood hero and inarguably the greatest living tennis player—perhaps the greatest ever—Serena Williams, a woman with more Grand Slam titles than Osaka has years on Earth.

Were you nervous to play Serena?

“My whole life, I’ve always wanted to play her,” Osaka says. “So I had nothing to be nervous about.”

Osaka stomped Williams in straight sets.

Boss Pullover / Adidas track pants / Adidas sneakers, $80

To understand Naomi Osaka, the brightest young talent in tennis, you don’t have to understand the sport. You need to know Overwatch. It’s a popular video game, and it’s the first thing she mentions when we start talking at Evert Tennis Academy in Boca Raton, Florida, where she usually trains, just a five-minute bike ride from her home. (Osaka plays for Japan, even though she’s lived in the U.S. since the age of three.)

On practice days, Osaka is on the court for four hours. Then she goes home and plays four, sometimes five hours of video games—mostly Overwatch with her older sister Mari. The game, a shooter where two teams of six square off, is composed of colorful cartoon characters, each corresponding to a class. There are more offensive types with a plethora of sci-fi weaponry, it being a video game and all. But Osaka prefers the defensive characters—“healers,” who support their teammates with medical aid, and “tanks,” who absorb bullets like a human shield.

“Like, I’m not that great at attacking,” Osaka says. “My aim is not that amazing, so I’d just rather be a shield or something.”

That’s funny, because I think people would describe your tennis playing as fairly aggressive and more offensive.

“Yeah, I’ve heard that a lot.”

So you are a very different Overwatch player than you are tennis player?

“Yeah, ummm…” A lot of our conversation is like this, Osaka’s sentences quietly trailing off into a void of polite laughs and ums.