Bobby Riggs: 1974 USA 'Tennis Centennial' first day cover signed 'Bobby Riggs', very fine condition. [Robert Larimore Riggs was a three-time grand Slam champion. However, he is most famous for his 1973 'Battle of the Sexes' matches against Margaret court, which he won, and against then current world number 1, Billie Jean King, which she won in three sets. At the time, court was 32, King was 30, and Riggs was 55 and long-retired from professional tennis!]