This rivalry makes the list because of an epic Davis Cup match played at Wimbledon on July 20, 1937. It was America against Germany, democracy against fascism. Millions around the world listened on the radio as Don Budge, a working-class player from Oakland, Calif., faced Gottfried von Cramm, a German aristocrat. Still, as Marshall Jon Fisher writes in his book on the match, A Terrible Splendor: Three Extraordinary Men, a World Poised for War, and the Greatest Tennis Match Ever Played, von Cramm was no Nazi stooge: a closeted homosexual, his Jewish doubles partner had recently fled Germany. The duo battled into the English twilight, with Budge winning 8-6 in the final set. Contested on the eve of a world war, the Budge-Van Cramm rivalry made clear that an era, as well as a tennis match, was coming to a close.