What has been the biggest Undefeated vs undefeated fight ever ?

[BoomBoom]

Leonard already lost to Duran before he fought Hearns
but thats one of the greatest fights of all time imo

my bad I meant to say leonard-duran.

its just that hearns is pretty much synonomous with leonard that subconciously I wrote leonard-hearns

Duran had already lost once before he fought Leonard.

DAMN, i don't know how I forgot about Estaban de jesus
for pointing that out

back.