(Reuters) - Naomi Osaka's Grand Slam title wins at the U.S. and Australian Opens have helped catapult the Japanese tennis player up to second, behind Serena Williams, in Forbes' list of the highest-paid female athletes over the last year.
Williams, a 23-times Grand Slam champion, topped the annual list for a fourth consecutive year with estimated total earnings of $29.2 million, the business magazine said.
Osaka's total income grew to $24.3 million, driven mainly by her off-court earnings, soaring to an estimated $16 million from $1.5 million a year ago, but the Japanese still missed the cut for Forbes' top 100 best-paid athletes list.
Williams is the only woman making it onto that list, coming in at No. 63.
Forbes said it compiled its list based on prize money, salaries, bonuses, endorsements and appearance fees between June 1 2018 and June 1 this year
U.S. women's soccer player Alex Morgan is the highest-placed non-tennis player on the women's list at number 12, with Forbes putting her total earnings of $5.8 million.
Morgan's income, which makes her the best-paid women's soccer player in the world, is dwarfed by that of Barcelona forward Lionel Messi, who topped Forbes' list of the best-paid athletes over the past year with $127 million.
The U.S. women's soccer team, who won a record-extending fourth World Cup this year, have filed a lawsuit against the country's national soccer body demanding equal compensation with their male counterparts.
Of the top 15 on Forbes' list of best-paid female athletes, 12 were tennis players. Indian badminton player P.V. Sindhu came in tied for 13th ($5.5 million), with Thai golfer Ariya Jutanugarn ($5.3 million) rounding out the top 15.
(Reporting by Simon Jennings in Bengaluru; Editing by Peter Rutherford)