Do you say she won because the man was 25 to 26 years older than her?
In my memory of the video news footage that I saw as a pre-teen the man who lost was deeply embarrassed that he lost.
Read up more - it was rigged. He beat the top female player in the world with ease in an earlier match and many believe he threw the King match to have his gambling debts to the mob erased.
In 1973, Riggs saw an opportunity to both make money and draw attention to the sport of tennis. He came out of retirement to challenge one of the world's greatest female players to a match, claiming that the female game was inferior and that a top female player could not beat him, even at the age of 55. He challenged Margaret Court, 30 years old and the top female player in the world, and they played on May 13, Mother's Day, in Ramona, California. Riggs used his drop shots and lobs to keep Court off balance;[24][25] his easy 6–2, 6–1 victory in less than an hour landed him on the cover of both Sports Illustrated and Time magazine.[25][26] The match was called the "Mother's Day Massacre".[27]
Riggs had originally challenged Billie Jean King, but she had declined, regarding the challenge as a fatuous gimmick. Following Court's loss to Riggs, King decided to accept his challenge,[28][29] and the two met in the Houston Astrodome on prime time television on Thursday, September 20, in a match billed as The Battle of the Sexes.[6] The oddsmakers and writers favored Riggs;[30] he built an early lead, but King won in straight sets (6–4, 6–3, 6–3) for the $100,000 winner-take-all prize.[7][8]
The ESPN program Outside the Lines[31] made an allegation that Riggs took advantage of the overwhelming odds against King and threw the match to get his debts to the mob erased. The program featured a man who had been silent for 40 years for reasons of self-protection who claimed that he had worked at a country club and heard several members of the mafia talking about Riggs throwing the match in exchange for cancelling his gambling debt to the mob. The program also stated that Riggs' close friend and estate executor Lornie Kuhle vehemently denied Riggs was ever in debt to the mob or received a payoff from them.
In the 2017 film adaptation Battle of the Sexes, Riggs was played by Steve Carell, with Emma Stone as Billie Jean King