Picture the greatest of your era, in his prime, just walking away in the middle of a game or main event. 'No Mas,' the supposed words uttered by Roberto  Duran, the best Latino boxer of his era, meant he could take no more. Was it punishment? Was it that his opponent Sugar Ray Leonard was hurting him? Was it that Leonard was annoying him? Until this day, nobody knows, but ESPN tries to clear the matter with Tuesday's 30 for 30 film, 'No Mas.' 

No mas in English means "No more." Duran had plenty more left after that fight, but that was the moment everybody remembered though the Panamanian boxer went on to fight 119 bouts in his career. He fought over 800 rounds, knocked out his opponent in 80 of his 119 fights. However, Duran will be remembered for that one fight. That one moment.  

Never mind that he was 29. Never mind that the year was 1980 and the fight was in New Orleans. When Duran, one of the most feared boxers of his time was out-dueled and outmaneuvered by the quicker Leonard, Duran could no more. 

It was sort of like a Michael Jordan moment, before Michael Jordan existed in the NBA. Jordan retired after winning three consecutive rings. Duran had just won the title, but he simply gave it up after the TKO against Leonard. He might not have retired from boxing, but it was difficult, like Jordan, why such a talented man simply gave up the WBO Welterweight title. 

ESPN brings you the documentary at 8 p.m. ET. You can watch it at home, but here is the live stream, free online. 

Click here to watch 'No Mas,' as one of boxing legends comes clean and tells his side of the store.