Nowadays, people judge Duran by the high-profile 80s fights at welter, middle, super-middle even, but he was old and faded and fighting way out of his weight-class though he still was a top competitor.

For 12 years, from 1968 till 1980, the prime Duran was smashing the living $#!t out of everybody.
135 lb Champ in 1972, the Great run culminated in 1980 by going up 12 lbs to 147 and defeating a prime undefeated Sugar Ray Leonard in a 15 rd battle.
Duran was 71 wins and 1 loss (avenged), 55 KOs going into that 1st Ray Leonard fight.