Canadian tennis player Bianca Andreescu was awarded $3.85 million for winning the 2019 U.S. Open women’s singles title. Men’s singles champion Rafael Nadal was also given $3.85 million. If this sounds like an abnormality for sports, it is. In fact, tennis is the only major sport in which men and women receive the same amount of prize money for winning Grand Slam tournaments.

Female tennis players are top-paid female athletes in the world. In fact, the only three women that crack the top 100 of the world’s highest-paid athletes are tennis players. For comparison, NBA players receive roughly $240,000 for winning the Finals while their WNBA counterparts only take home around $11,000.

Unsurprisingly, women’s tennis players had to fight hard to get their due. In the 1970s, Billie Jean King was getting paid a fraction as much as her male counterparts for winning the same tournaments. In what became known as the Battle of the Sexes, King faced off against former world No. 1 ranked men’s tennis player Bobby Riggs in a $1,000 winner-takes-all match on Sept. 20, 1973. King won the highly-publicized match, leading to a major shift in how the public viewed women’s tennis.

King continued her advocacy, later threatening to boycott the 1973 U.S. Open if male and female champions were not paid the same, making the Open the first major tennis tournament to offer equal prize money. The other three Grand Slam tournaments followed suit after the 1973 U.S. Open and have all paid equal prize money since 2007, when Venus Williams lobbied for Wimbledon to pay female champions the same as men.

While it may seem like the pay gap in tennis has closed, the reality is that at other large combined ATP-WTA tournaments, the prize money difference can be stark. At the Western & Southern Open in 2015, Serena Williams was paid $495,000 while Roger Federer received $731,000 for winning the same tournament.

While Grand Slam tournaments may give the impression that tennis pay is equal among men and women, the New York Times reported that the annual prize money for the top 100 earners in the Women’s Tennis Association is equivalent to just 80 cents to every dollar earned by the top 100 men in the Association of Tennis Professionals outside of Grand Slam tournaments.

However, the tennis organizations of ATP and WTP have made serious strides in creating similar fame and fortune for the athletes who put in the work to get to the top with Grand Slam tournaments paying the same prize money to both genders.

Hopefully, if other sports leagues follow suit and equalize prize money for winning titles, other female athletes could also get their share.

A version of this article appears in the Monday, Sept. 16, 2019, print edition. Email Danial Hashemi at [email protected].