Billie Jean King beats Bobby Riggs in the Battle of the Sexes tennis match at the Houston Astrodome.

In tennis, "Battle of the Sexes" describes various exhibition matches played between a man and a woman, or a doubles match between two men and two women in one case. The term is most famously used for an internationally televised match in 1973 held at the Houston Astrodome between 55-year-old Bobby Riggs and 29-year-old Billie Jean King, which King won in three sets. The match was viewed by an estimated fifty million people in the United States and ninety million worldwide. King's win is considered a milestone in public acceptance of women's tennis.

September 20 is the 263rd day of the year in the Gregorian calendar; 102 days remain until the end of the year.