Organización Mundial de Boxeo
On September 11, 2004, Cotto faced Kelson Pinto from Brazil, for the vacant World Boxing Organization junior welterweight title. This represented the third fight between them, with Pinto being victorious in their two previous encounters, both of which took place while they were still amateurs. The fight was televised by HBO from San Juan, Puerto Rico. During this card Cotto utilized a defensive stance with his hands in a high position instead of his usual aggressive orthodox stance. Over the course of the fight Cotto scored three knockdowns and won the World Boxing Organization Junior Welterweight Championship by knockout in the sixth round.