Battle of the Sexes: 50 years on from Billie Jean King's landmark victory

The world of tennis is this week celebrating the 50th anniversary of Billie Jean King beating Bobby Riggs in the historic "Battle of the Sexes".

The exhibition match between King, who was 29 and the world's No.1-ranked woman player at the end of 1972, and Riggs, "a cocky 55-year-old once ranked No.1 in the world", took place at the Houston Astrodome on 20 September 1973.

It was the "most watched tennis match of all time", said CNN, with an estimated "90 million people tuning in worldwide". It took place after Riggs claimed he could still beat a top female player, despite his age, and King, who led efforts for women players to receive the same prize money as men, took up the challenge.

King's straight-sets win (6-4 6-3 6-3) was a "career-defining moment", said People magazine, especially as the previous year she had threatened never to play tennis again after receiving only $10,000 for her US Open win, "$15,000 less than what the men's winner was awarded".

In the Battle of the Sexes, she received $100,000 – "but the real prize was what it meant for women's sports and the fight for equality", CNN said.

"I thought it would set us back 50 years if I didn't win that match," King said. "It would ruin the women's tour and affect the self-esteem of all women."

King's work appeared to come full circle this month when she presented 19-year-old Coco Gauff with a cheque for $3 million after the American teenager secured her first grand slam win at the US Open.

A week later, King referenced Gauff's win, acknowledging the legacy she had created with the Battle of the Sexes.

"Coco winning was just fantastic," King, now 79, told People. "When I see her, she's the reason we fought so hard 50 years ago."

Referring to her victory over Riggs, she said "sometimes it feels so long ago, and other times it feels like today".