Naomi Osaka entered the U.S. Open last year largely under the radar as the 19th-ranked player in the world. But that all changed with her run to the finals and memorable win over Serena Williams. When Osaka backed up the Open title with a second straight slam win at the Australian Open in January, the next marketing superstar was born.

Osaka’s accomplishments, youth, skill and multicultural appeal make her a marketer’s dream. Born to a Japanese mother and Haitian-American father, she was the first Japanese person to win a Grand Slam event and first Asian player to hold the top ranking in singles.

Her off-court earnings jumped from $1.5 million annually to an estimated $16 million for the 12 months ending June 1, after signing deals with Mastercard, All Nippon Airways, Nissan and Procter & Gamble.

Her endorsement haul will be even greater over the next year after signing a blockbuster, multimillion-dollar pact with Nike in the spring, just ahead of our earnings cutoff. Osaka, 21, is primed to be one of the faces of the 2020 Summer Olympics in Tokyo.

Including prize money, Osaka’s total earnings were $24.3 million by Forbes’ count. It makes her just the third female athlete to earn $20 million in a year, joining fellow tennis aces Williams, Maria Sharapova and Li Na.

Osaka’s big payday still trails that of Williams, who is the world’s highest-paid female athlete for the fourth year in a row. She earned $29.2 million, including $4.2 million in prize money, after returning to the WTA Tour following the birth of her daughter, Olympia, in September 2017.

Williams continues to expand one of the most robust endorsement portfolios in sports, adding Pampers, Axa Financial and General Mills to her roster. They join more than a dozen other brands like Nike, Beats, Gatorade and JPMorgan Chase.

The 23-time Grand Slam champ scores highly across all demographics, and only Tiger Woods and Tom Brady have higher levels of awareness among athletes with U.S. consumers. Williams’ $225 million estimated net worth makes her the only athlete on Forbes’ list of America’s Richest Self-Made Women.

Williams and Osaka both earned more than twice as much as the third-highest-paid female athlete in the world, Angelique Kerber, who pulled in $11.8 million from tennis.

Tennis remains the most surefire way for female athletes to make millions of dollars. Witness the WTA Tour’s announcement last week that the year-end WTA Finals event will pay its winner $4.7 million this year. It is the largest payout in the history of men’s or women’s tennis. Total prize money on the WTA Tour is $179 million in 2019, and the 10 highest-paid female athletes in the world this year are all tennis players (women from golf, soccer and badminton crack the next five).

Female athletes in soccer, basketball and softball earn salaries of pennies on the dollar compared with their male counterparts. The WNBA max salary slot this season is $117,500, compared with $37.4 million in the NBA.

Despite the playing salary gap in team sports, marketing opportunities have opened up in recent years for female athletes thanks to the growth of social media platforms, according to Dan Levy, who heads up the Olympics and female athletes divisions at Wasserman.

“Pro athletes now have a way to connect with their fans that doesn’t rely on network TV to build a fan base and connectivity to the consumers that brands want to reach,” Levy says. “That change alone has helped women become much more powerful in the sports marketing world.”

Wasserman, which represents Alex Morgan, Megan Rapinoe and Katie Ledecky among its 2,000 clients, launched a new service, Athlete Exchange, last month to help match athletes who have robust digital presences with brands chasing a desired audience. Wasserman client Hilary Knight does not get a lot of air time as a member of the U.S. women’s ice hockey team, but her online profile has more social interactions than all but six NHL players in 2019. The engagement is a boost for her endorsement partners like Red Bull, Visa and Bauer Hockey.

Our earnings tally looks at prize money, salaries, bonuses, endorsements and appearance fees between June 1, 2018, and June 1, 2019. There are 15 female athletes who made at least $5 million during that time period; for comparison roughly 1,300 male athletes will hit that mark this year. The top 15 earned a cumulative $146 million, compared with $130 million last year. It’s an international crew with athletes from 11 different countries represented.

15. Ariya Jutanugarn

Total Earnings: $5.3 million

Prize Money: $3.3 million

Endorsements: $2 million

Jutanugarn won the LPGA Tour’s Race to the CME Globe season-long points competition and the accompanying $1 million bonus. The Thai pro golfer has more than 10 endorsement partners, including Titleist, Toyota, KBank and Thai Airways.

13 (tie). Madison Keys

Total Earnings: $5.5 million

Prize Money: $2.5 million

Endorsements: $3 million

Keys reached a pair of Grand Slam finals in 2018 (French Open and U.S. Open) and won her first clay court event of her career at the Charlestown Open this year. Nike is her biggest endorsement, and she also counts Evian, Wilson and Ultimate Software as partners.

13 (tie). P.V. Sindhu

Total Earnings: $5.5 million

Prize Money: $500,000

Endorsements: $5 million

Sindhu remains India’s most marketable female athlete. The badminton star has endorsements with Bridgestone, JBL, Gatorade, Panasonic and more. She became the first Indian to win the season-ending BWF World Tour finals in 2018.

12. Alex Morgan

Total Earnings: $5.8 million

Salary: $250,000

Endorsements: $5.5 million

The biggest star of the U.S. Women’s National Team says she’ll be back in uniform for the 2023 World Cup and is bringing personal sponsors like Nike, Coca-Cola, Beats, AT&T, Continental Tires and Volkswagen along for the ride. The USWNT co-captain is planning to launch a media company focused on women in sport.

10 (tie). Garbine Muguruza

Total Earnings: $5.9 million

Prize Money: $2.4 million

Endorsements: $3.5 million

Earnings fell for the two-time major winner as her ranking dropped to a recent No. 28 from second in the world at the end of 2017. She still maintains a deep endorsement roster with Adidas, Evian, Beats, Rolex and Babolat.

10 (tie). Venus Williams

Total Earnings: $5.9 million

Prize Money: $900,000

Endorsements: $5 million

The 39-year-old Williams invested in wellness brand Astura and was appointed chief brand officer of the company in May. The 23-time Grand Slam champion, including doubles, launched her own YouTube channel last month focused on “fitness, tennis, wellness, design and more.” Williams can bank six-figures a pop on the speaking circuit.

9. Elina Svitolina

Total Earnings: $6.1 million

Prize Money: $4.6 million

Endorsements: $1.5 million

Svitolina scored the biggest win of her career when she captured the WTA Finals title in Singapore to end the 2018 season. The Ukrainian-born pro pocketed $2.4 million for the win and finished the year with a No. 4 world ranking, triggering bonuses from sponsors Nike and Wilson.

8. Karolina Pliskova

Total Earnings: $6.3 million

Prize Money: $4.6 million

Endorsements: $1.7 million

The Czech-born Pliskova has won four events over the past 12 months but has not reached a slam final since losing the 2016 U.S. Open. Pliskova bumped her off-court earnings with a new contract with FILA that kicked in this year.

7. Maria Sharapova

Total Earnings: $7 million

Prize Money: $1 million

Endorsements: $6 million

Injuries limited Sharapova to only 18 matches over the past year, but she maintains a lucrative endorsement with Nike, in addition to her Porsche, Head, Evian and Tag Heuer partnerships. Sharapova invested in the UFC and skincare brand Supergoop, yet her main off-court focus is building her candy brand Sugarpova.

6. Caroline Wozniacki

Total Earnings: $7.5 million

Prize Money: $3.5 million

Endorsements: $4 million

Wozniacki won a trio of events in 2018 and ranked among the top three players during the entire year. She married former NBA player David Lee in June. The wedding brought together stars from their respective sports with Serena Williams a bridesmaid and other attendees including Angelique Kerber, Pau Gasol and Harrison Barnes.

5. Sloane Stephens

Total Earnings: $9.6 million

Prize Money: $4.1 million

Endorsements: $5.5 million

Stephens reached the finals of four events last year and finished the year ranked No. 6 overall. Her Nike pact, which began last year, is one of the biggest in the sport. She showcased a tennis shoe based on the “Aqua” colorway of Nike’s retro Air Jordan VIII this summer.

4. Simona Halep

Total Earnings: $10.2 million

Prize Money: $6.2 million

Endorsements: $4 million

Halep had the top prize money in the sport in 2018 and ranks fifth on the all-time list with $33 million. She won Grand Slam titles each of the past two years, triggering lucrative bonuses. The Romanian pro counts Nike, Wilson, Mercedes-Benz and Hublot among her sponsors.

3. Angelique Kerber

Total Earnings: $11.8 million

Prize Money: $5.3 million

Endorsements: $6.5 million

Kerber won Wimbledon in 2018 and finished the year ranked second in the world, triggering bonuses from her partners. She renewed deals with Adidas, SAP, Generali and NetJets and recently inked a new pact with Procter & Gamble’s Head & Shoulders brand. Other endorsements include Yonex, Porsche, Rolex and Lavazza.

2. Naomi Osaka

Total Earnings: $24.3 million

Prize Money: $8.3 million

Endorsements: $16 million

Nike shocked the tennis world when it announced in April it secured Osaka to an endorsement deal. Most observers thought she would return to Adidas, which had Osaka under contract until her deal expired at the end of 2018.

1. Serena Williams

Total Earnings: $29.2 million

Prize Money: $4.2 million

Endorsements: $25 million

Williams, 37, plans to play through at least next year but is already planning her next act with a clothing line, S by Serena, and designs to launch jewelry and beauty products lines by the end of 2020. She also has built a venture portfolio worth more than $10 million.