NEW YORK, USA - At 21-years-old, Naomi Osaka is still not accustomed to looking across the net at a younger, less experienced opponent. Despite being World No.1 and a two-time major champion, Osaka is used to being the youngest person in the room, the one still sponging up experience both on and off the court. 

But the teenage surge on the WTA Tour in 2019 has led to an immediate seachange, one that actually kicked off Osaka's season when she played her first match of the year against 18-year-old Destanee Aiava in Brisbane. Then came a fantastic duel with 18-year-old Iga Swiatek in Toronto earlier this month, which led to a practice session in New York

At the draw ceremony in Toronto, seated next to Bianca Andreescu, the 19-year-old Canadian said she was inspired by Osaka's success. It's a sentiment you hear often when asking the younger set about Osaka. 

If Naomi can do it, why can't we? If Naomi can do it, what are we waiting for? If Naomi can do it, our time is now. 

"I can't be all soft and squishy. Gotta put the hammer down. I might be old, but I can still win a couple of matches."

- Naomi Osaka

In the wake of Osaka's incredible 18 months, which saw her win Indian Wells, the US Open, the Australian Open, and rise to No.1, a surge of young talent have jostled their way into the spotlight and they're quick to credit her example. 

To no one's surprise, Osaka says she's still adjusting to it. 

"It's an odd feeling, but then I realize how old they are and I think there's always a new generation," Osaka said in Cincinnati. "It's definitely very strange but I think it's something I have to get used to.

"But at the same time I can't be all soft and squishy. Gotta put the hammer down. I might be old, but I can still win a couple of matches," she said before breaking into laughter.

There will be no time for squishy behavior for Osaka on Saturday, where she will face 15-year-old Coco Gauff in the third round of the US Open. It is the marquee match of the third round and one that will surely have Arthur Ashe Stadium rocking given the excitement around Gauff's prospects. 

But if fans are looking any extracurricular spice, they'll have to look elsewhere.

"I practiced with her, I think I was 13, at Miami Open," Gauff told reporters after her dramatic three-set win over Timea Babos in the second round. "That was super cool. 

"I was able to keep the ball on the court. I was super nervous. She's prepping for a tournament so I didn't want to mess up her practice.

"But she's a super sweet person. I mean, my dad and her dad have known each other for a long time. They always talk all the time. 

"She's a great person. She's nice. Her mom is one of the nicest people ever. She's so amazing. Her whole family is just great."

Osaka said she sees a more put-together version of her young self when she sees Gauff in the locker room. 

"Off the court she seems like me," Osaka said. "Well, she seems a little bit more like she knows what she's doing."

"I saw her in the locker room, and she just had her headphones on. I was, like, Oh, looks familiar. I just went up and talked a little bit. She's super sweet.

"I know she's super young, and I know it's sort of hard to transition. I wasn't even a junior, 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. 

"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."

On Saturday, Osaka and Gauff will put their burgeoning friendship aside for the first installment of a burgeoning on-court rivalry. The match will be a test for both women. 

"I'm just curious to see how my game matches up against her. Obviously I want to win."

- Coco Gauff

For Gauff, it will be a test of her game. The youngster is looking to make the Round of 16 at a second consecutive major after doing so at Wimbledon, and Osaka's high-octane game will be a big step up from the opposition she's faced so far in her young career. The highest-ranked player Osaka has beaten in her career is No.44 Venus Williams at Wimbledon, and in her first career match against a Top 10 player, Simona Halep handled her with relative ease in a 6-3, 6-3 win at Wimbledon. 

Osaka's serve and forehand have been clicking so far in New York and it will be interesting to see how Gauff handles the cross-court forehand rallies that Osaka can dominate. 

"Honestly, I think she's a big inspiration for everyone," Gauff said. "She's 21. She has two slams. She's still striving for more.

"I think she's just a super sweet person on and off the court. She competes great out there. I think she shows us how to compete and the way to be off the court, too.

"We're both pretty young, but I'm a little bit newer to the game. So I'm just curious to see how my game matches up against her. Obviously I want to win."

For Osaka, the match will be a test of her nerve. The largest tennis stadium in the world will be jam-packed and, one would anticipate, highly partisan against her. This is not a new experience for Osaka - flashback 12 months here - but this time she is the favorite to win and the bearer of the pressure. 

Osaka says she's more curious than anything to see Gauff from up close. 

"For me, when I hear people talking about someone, I want to have the opportunity to play them just to assess it for myself."

Before facing Swiatek in Toronto, Osaka was asked what she expected against the Polish teen. Her answer provided a knowing glimpse of an accomplished player who is still young enough to remember what it was like to step on court with nothing to lose and nothing to prove. 

"She's young, and young people usually have no fear," Osaka said then. 

"I know that from experience."