The Swiss tennis great, owner of a men's record 20 Grand Slam singles titles, earned $106.3 million in the last 12 months, including $100 million via endorsements, to move up four places and become the first player from his sport to top the list.
The ongoing coronavirus pandemic that shut down sports worldwide caused the first decline since 2016 in the total income of the world's 100 top-paid athletes, a 9 percent dip from last year to USD 3.6 billion. Another plunge is expected next year from the shutdown.
Ronaldo was second on the list at USD 105 million, USD 60 million in salary and USD 45 million from endorsements, with Messi third on USD 104 million, USD 32 million of that from sponsorship deals. Messi and Ronaldo, who have traded the top spot three of the past four years, saw their combined incomes dip USD 28 million from last year due to salary cuts when European clubs halted play in March.
Neymar was fourth overall on USD 95.5 million, USD 25 million from endorsements, while LeBron of the Los Angeles Lakers was fifth on USD 88.2 million, USD 60 million of that from endorsements.
"The coronavirus pandemic triggered salary cuts for football stars Messi and Ronaldo, clearing the way for a tennis player to rank as the world's highest-paid athlete for the first time," said Kurt Badenhausen, senior editor at Forbes.
"Roger Federer is the perfect pitchman for companies, resulting in an unparalleled endorsement portfolio of blue-chip brands worth $100 million a year for the tennis great."
NBA star Stephen Curry of the Golden State Warriors was sixth on USD 74.4 million with former teammate Kevin Durant next on USD 63.9 million.
Tiger Woods, the reigning Masters champion and a 15-time major winner, was eighth on the list and tops among golfers at USD 62.3 million, all but USD 2.3 million from sponsor deals.
Woods topped the Forbes list a record 12 times before an infidelity scandal helped end his run.
Two NFL quarterbacks rounded out the top 10 with Kirk Cousins ninth at USD 60.5 million and Carson Wentz 10th on USD 59.1 million.
Osaka and Williams were the only women on the list.
Basketball players led all sports with 35 players among the top 100. American football occupied 31 spots, none higher than six-times Super Bowl champion Tom Brady ($45 million) who was ranked 25th.
Football was the next most represented sport with 14 players, followed by tennis (six), boxing and mixed marital arts (five), golf (four), motor racing (three), and baseball and cricket with one each.
(With inputs from Reuters and AFP)