Billie Jean King was a legend in women's tennis based on her raw talent and success in the sport, but what truly cemented her as a household name for years to come was when she defeated male tennis star and former world number one Bobby Riggs. 

In case you're unfamiliar with the match, Riggs was kind of a jerk. After initially challenging King only to be turned down, the 55-year old Riggs beat the number one female at the time - Margaret Court - and went on to basically brag that no female in the world could beat him. He was so confident that he put $100k on the table. 

King decided to take on the braggadocios male counterpart. On September 20th, 1973, the two tennis players met at the Houston Astrodome in front of over 30,000 spectators. That is still the largest audience to witness a tennis match in the United States. The match is dubbed the Battle of the Sexes.

Jean was the heavy underdog, but she managed to pull off an upset in straight sets. It marked a monumental moment in women's sports and is still referred to as one of the most important sporting events to ever take place. 

Now, it is breaking more records in women's sport. 

The racket that King used during the famous tennis match was auctioned off on Wednesday for an astonishing sum of $125,000. According to Ben Rothenberg of the New York Times, this is believed to make the famous racket the most expensive piece of women's sport memorabilia all-time. 

While the sale was made by a private seller, they have generously contributed 10 percent of the money to the Women's Sport Foundation - a non-profit charity founded by King. The sale happened at an opportune time, as a major motion picture starring Emma Stone and Steve Carrell was released less than three months ago. 

(H/T Last Word on Tennis)