She also outranked New England Patriots quarterback Tom Brady , #81. With six Super Bowl rings and an average annual salary of $15 million, Brady is "one of the NFL's best bargains."

Coming in at #63, Williams has a stable of more than a dozen corporate partners and a startup portfolio worth at least $10 million, according to Forbes . She's earned $89 million in prize money throughout her career, double that of any other female athlete.

Serena Williams is the only woman to crack the ranks of Forbes' 2019 list of the world's highest-paid athletes.

Barcelona's Argentinian forward Lionel Messi celebrates after scoring during the Spanish league football match between FC Barcelona and Girona FC at the Camp Nou stadium in Barcelona on February 24, 2018.

Forbes ranks athletes for this list by adding up prize money, salaries and endorsement dollars earned between June 2018 and June 2019. The top 100 athletes this year come from 25 countries, span 10 sports and earned a combined $4 billion, a 5% bump from last year.

Williams did not appear on Forbes' list in 2018, having taken time off after giving birth to daughter Alexis in September 2017. But it isn't the first time she's been the only woman to appear on this list — she was #51 in 2017. No women appeared on the list in 2018.

The highest-earning athlete in 2019 is soccer star Lionel Messi, 31, who bumped retired boxer Floyd Mayweather Jr. (who fell off the list this year) from the No. 1 spot with $127 million in earnings – including his contract with Barcelona, which pays him over $80 million a year through 2020-21, and a lifetime deal with Adidas.

Following behind him in the No. 2 and 3 spots are competitors Cristiano Ronaldo and Neymar.

Superstar athletes are not only earning more on the fields, but endorsement deals now separate the ultra-wealthy from the merely rich. At $25 million, cricketer Virat Kohli earned the least of the athletes on this list over the past year — a significant increase from the $17.3 million earned by the No. 100 spot just five years ago, Forbes reports.