Watch Arthur Ashe - More Than a Champion on BBC Two on Friday 26 June, from 21:00 BST.
Opposites do not attract. Rarely is there admiration between clashing personalities.
Sometimes the animosity and ill will can be all-consuming and sometimes these adversaries will scrap before a watching world. It is then that the rivalry becomes gripping.
"I swear, every time I passed Jimmy Connors in the locker room, it took all my willpower not to punch him in the mouth," recalled Arthur Ashe.