Naomi Osaka strikes it rich - Her $20 million-dollar week

US Open champion Naomi Osaka. Photo / AP

Her first Grand Slam title may have been overshadowed by what happened between Serena Williams and a chair umpire, but Naomi Osaka's star is clearly on the rise after winning the U.S. Open last week.

Osaka, the 20-year-old who beat Williams in straight sets Sunday am (NZT), has signed on as a brand ambassador for Nissan, a move that shows both her international appeal to fans and her value to advertisers.

"Growing up, my dad drove a Nissan, so being able to be a brand ambassador now, it feels like I've come full circle," she said overnight, speaking at the car company's headquarters in Yokohama, according to Reuters.

Osaka is also reportedly about to land the biggest deal Adidas has ever given a female athlete - possibly in the US$10 million (NZ$15m) range. That's on top of the US$3.8 million (NZ$5.8) she took home in prize money after topping Williams.

Add the Nissan deal and she's looking at more than NZ$20m earned in the last week.

Winning in New York was particularly important in driving up Osaka's value to sponsors, because the people who make advertising decisions and work for major brands "were physically in the building," sports marketing consultant Joe Favorito told the New York Post. "The fact that she succeeded in New York gives her another one-up."

In a bit of happy timing, her four-year deal with Adidas, reportedly in the low six figures, was set to expire later this year. That means "her brand value for Adidas is in the millions now," according to Favorito. The company was quick to add her to its "Creators Unite" campaign.

Osaka also has had deals with Yonex, Nissin Foods, Wowow and Citizen Watch.

Being a star in Japan gives her a better chance to conquer the Asian market, too, and her IMG agent, Stuart Duguid, predicted to The London Times that her marketing potential will now be "through the roof." (Osaka was born in Japan but grew up in the United States; her mother is Japanese and her father is Haitian.)

"We manage Kei [Nishikori], too, so we know how strong that market is for endorsements. The blueprint was there," Duguid said (via the Daily Mail). 'There's a lot of companies for whom Kei is the male and they are looking for a female, so it couldn't be better timing. Her clothing deal is up at the end of the year, so we are in discussions with pretty much everyone on that."

Osaka cashed in on her deal with Citizen, too, earning a bonus because of the attention she got for wearing the company's watches. Noriyuki Mitome, a Tokyo-based spokesman for the company, declined to disclose details of the bonus to Bloomberg.

"We were already sort of managing her at IMG as one of our star female clients just based on her game, the way she looks on court," Duguid told the Mail. "She's from Japan with a multicultural background from Haiti and the United States, so she has the full package. She is very honest and down to earth and people are relating to that. She's going to have a very successful career on and off the court."