After retirement from his pro career, Riggs became well known as a hustler and gambler. He organized numerous exhibition challenges, inviting active and retired tennis pros to participate. In September 1973, at age 55, he held one such event against the then current women's champion Billie Jean King, which he lost. Their prime time "Battle of the Sexes" match remains one of the most famous tennis events of all time, with a $100,000 ($ today) winner-take-all prize.