Emanuel Navarrete stopped Eduardo Nunez before the start of the 11th round to unify the WBO and IBF super-featherweight titles in Arizona on Saturday night.
The three-division champion prevailed in the pair's all-Mexican clash to improve his record to 40-2-1 (33 KOs), while Nunez dropped to 30-2 (28 KOs) in the biggest fight of his career to date.
Navarrete clinched the IBF title to accompany his WBO belt when the doctor at ringside stopped the contest ahead of the 11th round.
"It's difficult to see your opponent hurting in there, but it's also really difficult to not continue and go on to win the fight," said Navarrete.
"You never know what might happen in those last rounds. He could catch you with a shot and it could be over. So I needed to continue doing my work."
Navarrete dominated much of the fight in the face of Nunez's effort to switch up styles, willing to meet his opponent on the inside in the early rounds before weathering some work to the body from Nunez.
Navarrete stepped up his attack in the ninth round by landing a string of right hands to the chin of Nunez, whose legs were wobbling and eye closing up.
Blood poured from the right eye of Nunez in round 10, but he refused to back down until the ringside doctor called time on the bout.
Navarrete looks primed to face WBO mandatory challenger Charly Suarez next, the pair having fought to a no-contest last May.
