Roberto Duran UD 15 Sugar Ray Leonard, June 20, 1980:

This was the fight that kicked off one of boxing's greatest eras, the age of "The Four Kings," the nickname collectively assigned to Sugar Ray Leonard, Roberto Duran, Thomas Hearns and Marvelous Marvin Hagler by sports writer George Kimball, in his book of the same name. 

Leonard was sport's emerging golden child, taking over for the retired Muhammad Ali as the face of boxing. He even shared Ali's trainer, Angelo Dundee. After establishing himself as a household name by winning gold in the 1976 Olympics, Leonard had cruised through the professional ranks, winning the WBC welterweight belt from the great Wilfred Benitez in 1979.

Duran was already a living legend when he moved up in weight to challenge Leonard. Throughout the 1970s, he had compiled a record of 71-1 and established himself as arguably the greatest lightweight in history.