But now that Gauff has joined Osaka as a pro on tour (insofar as she's allowed to play at 15), they've gotten to know one another more as peers, and they even seem to have a budding friendship.
"I saw her in the locker room. She wasn't really talking to anyone," Osaka said. "I was, like, Oh, looks familiar. I'm just going to talk to her. I know she's super young, and I know it's sort of hard to transition."
"I wasn't even a junior," Osaka went on, "but I can only imagine: As a junior you play these tournaments with your friends, and then you come to the pros and you don't know anyone. I'm just, like, Oh, she's a really talented girl. I would love for her to come out of her shell a little bit. I just realized that's probably what people say about me, too."
"Off the court she seems like me. Well, she seems a little bit more like she knows what she's doing," Osaka joked.