The tennis racket used by Billie Jean King during the epic “Battle of the Sexes” match is set to sell for $200,000 at auction.

On September 20, 1973, Wimbledon Champion Billie Jean King played a $100,000 purse best-of-five match against former Wimbledon and US Open champion Bobby Riggs.

Riggs, then 55, had claimed the women’s game was inferior to the men’s and, despite, his age, he could beat the best of the opposite sex.

The American did beat Margaret Court and then King, 29, accepted his challenge to a match.

They faced each other in Houston, Texas, and King thrashed her male rival — winning in straight sets 6-4, 6-3, 6-3.

It came at a time when equality in sports was a hot topic.

Margaret Court had won the grand slam in 1972, earning a bonus of $15,000. However, a similar bonus on the men’s circuit would have been $1 million.

The match inspired a generation of young girls to compete both on and off the field to show boys they were equals.

Around 90 million people watched the “Battle of the Sexes” match on TV and the spectacle was just made into a Hollywood movie starring Emma Stone and Steve Carell.

Bonhams has announced it will be selling the wooden racquet used by King at its “Voices of the 20th Century” auction in New York on December 6. It has been given a guide price of $100,000 to $200,000.

The Wilson racket has a market leather handle from use and a number of minor chips and scratches.

It is one of only two rackets used by King during her epic match, and the only one whose whereabouts are currently known.

King donated the racket to charity in 1982 and it was bought by its current owner in 1996.

They are now selling it with a portion of the proceeds going to the Women’s Sports Foundation.