On Saturday morning, as the crowd in the Billie Jean King National Tennis Center waits for Naomi Osaka to walk out for her third-round match in the U.S. Open, the cheers are likely to begin long before she even emerges from the tunnel. Attendees have been thrumming with anticipation: not just about how each competition will go, but about what Osaka will wear. No one has done more to change the game of tennis fashion this year than Osaka.

At every Grand Slam she has raised the bar, and at the Open, the last major tournament of the year, it had become clear that this time around she was offering something of a grand finale. Osaka wasn’t just unveiling a unique on-court Nike-designed look, as she, and tennis stars like Maria Sharapova and Serena and Venus Williams, had done before. She wasn’t just wearing a startling walk-on look that was more catwalk than court, as athletes do in basketball and football.

She was wearing a veritable collection created by multiple designers. One that honored both New York fashion and the sports stars who preceded her. Coming just days before New York Fashion Week is scheduled to start, her entrances served as a curtain raiser for an entirely different kind of audience — one that positioned Osaka as a new kind of influencer."I think we’re really coming into a tennis renaissance age where so many players are embracing fashion, and Osaka is at the forefront of that," said Sunita Kumar Nair, the author of "Ace: The Times & Style of Tennis."The pageantry began during Osaka’s pretournament practices at Flushing Meadows Corona Park in Queens, when she paid homage to a famous 2003 photograph of Anna Kournikova arriving at the tennis complex wearing a minidress and Valentino heels and carrying a Vuitton bag.

Only she raised it one, making every arrival a fashion moment even before the Open began. Practice Day 1 was a diaphanous tangerine miniskirt and strapless top; Day 2, a draped caramel mini; Day 3, a ruched turquoise number, and so on. And it really came into focus at the tournament, when Osaka decided for the first time to wear three different designer looks, one for each of her possible early match entrances — all inspired by the basketball player Allen Iverson to match the basketball theme of Nike’s U.S. Open kit — and had enlisted the "image architect" Law Roach to help realize her plans.

The first look: an asymmetrical gray hoodie from Who Decides War, the sleeves cut off and one side of the hem stretching to the ankle, atop a wedding cake-like white tulle skirt. The second one: a sheer Thom Browne jacket embroidered with little silver rackets atop a long pleated skirt open at the front so it appeared like a train (with matching looks worn by her mom and publicist, as well as other members of her support team). The third one: a Monse look to come.

And there may be more combinations of the pieces she has already worn if Osaka advances in the tournament. Still, whatever happens with the trophy, one thing is clear: Osaka has permanently changed expectations around tennis and dress. Even if she didn’t mean to do that in the beginning, exactly.

Learning to Serve Looks as Well as Aces"I feel like I’ve always had the idea in my head," Osaka, 28, said a few days before the Open as she was getting her hair and makeup done before a cookout she was hosting in Dumbo. She was wearing a pair of jeans covered in upcycled patches from Boston and New York teams that she had discovered on a shopping stroll in Brooklyn."But I also feel that in Japanese culture, we always follow the rules," she said. "And I didn’t know if I would be breaking the rules to be so fashionable. I felt like I needed to get permission to do that."Her breakthrough, she said, was the Yoon Ahn Nike dress she wore to play in the U.S. Open in 2024, at a time when she was struggling to return to tennis after the birth of her daughter.

The dress, inspired by Harajuku, featured assorted ruffles and bows. (Osaka grew up in New York and Florida, and h...