The 139th U.S. Open kicks off in New York City next week. And Naomi Osaka, one of the biggest names in tennis, will be there to defend her title.

At 21 years old, Osaka is the second-highest paid female athlete in the world, according to Forbes. Osaka won last year's Open, defeating tennis legend Serena Williams on her way to back to-back Grand Slam victories.

Despite her soaring celebrity and influence, Osaka tries to stay grounded. She continues to look up to Williams, her life-long role model — even if she still feels "nervous" to talk to her.

"I have this huge respect for her. It's someone that I've, you know, looked up to my entire life. So I still feel a bit shocked whenever she reaches out," Osaka said. "And, I don't know. I don't say hi to her or anything because … I get so nervous."

"She always seems like she's doing something important, so I don't want to interrupt," Osaka added. "And then — I really want to talk to her about life and stuff and, like, how she manages to do things on and off the court. But … I don't wanna be disrespectful to her and, like, try to talk to her like she's my mentor while she's still playing. So I'm kinda just chillin' on that."

"Do you think you would reach out to her just to see?" asked CBS News' Vladimir Duthiers.

"I mean, I would, but — I'm nervous," Osaka said with a laugh.

And despite beating Williams at least year's Open, Osaka said she doesn't see the tennis legend as a peer.

"I would have to win 20-something more Grand Slams to be her peer," Osaka said. "She has so many lists of accomplishments. So no way."

"I've just been very grateful that I'm even playing," she added. "I've been trying to, like, take every day as a new experience and learn from everything."

Osaka's nervousness doesn't show on the court, where she's a whirlwind of competitive intensity balanced by poise and grace.

At just 21, she's already reached the pinnacle of her sport. When Duthiers met her in New York, she was in the middle of an event for BODYARMOR Sports Drink, a company in which she's a partner and investor.

Being the best comes with pressure to stay there. "I mean, the internal pressure isn't as bad — OK, I lie when I say that, because I just realized, like, I do put a lot of pressure on myself," Osaka said. "Because, you know, having the number one ranking means that you're supposed to be the best."

But after winning back-to-back Grand Slam titles, Osaka lost her next two Majors. In July, she was eliminated from Wimbledon in the very first round.

In a recent Instagram post, Osaka called the last few months "the worst of my life."



"For tennis players … we train so hard just for that one moment or that one match on the court," she told Duthiers. "It's just a really high high if you win, or a really low low if you lose."

But Osaka said that she doesn't plan to let those losses keep her down. "One of the biggest things I've learned over the summer is … just to keep getting back up," she said. "Believe in yourself and have fun."

"And tennis is fun?" Duthiers asked.

"I think there are moments where it stops being fun for me," Osaka said. "But then I realize that I'm super grateful to be in the position that I'm in."