A week and a half ago tennis crowned a new queen when Angelique Kerber lifted the US Open to mark her ascent to the World No.1 ranking.

Watching on from the stands was Billie Jean King, the woman after whom tournament’s home is named, and who 43 years earlier paved the way for Kerber and company by defeating Bobby Riggs.

Dubbed by promoters as ‘The Battle of the Sexes’, on September 20, 1973 King took on Riggs, an ageing former major champion and shameless misogynist who claimed he could still beat any of the leading women on the fledgling Women’s Tennis Association.

Luckily, she did win. Playing to an audience of 30,472 in the Houston Astrodome – and over 100 million watching around the world on television – King abandoned her serve-and-volley game to defeat Riggs from the back of the court, 6-4, 6-3, 6-3.

When Riggs hit a high backhand volley into the net on match point, King flung her racket into the air in celebration. “I thought it would set us back 50 years if I didn’t win that match,” she said later. “It would ruin the women’s tour and affect all women’s self-esteem.”

For his part, Riggs told reporters that King simply “played too well.” The two eventually became friends, and even spoke a few days before Riggs died of prostate cancer in 1995.

Over four decades on, the match remains a landmark moment in the gender equality movement, one that transcended sport.

43 years ago today I played Bobby Riggs in a match that changed my life & was all about equality. To celebrate let's shine a light on others

— Billie Jean King (@BillieJeanKing) September 20, 2016