Mexico's Emanuel Navarrete stopped compatriot Eduardo Nunez in a dominant display to unify the IBF and WBO super-featherweight titles.
After outclassing Nunez for much of the contest, Navarrete, 31, added the IBF title to his WBO crown when the ringside doctor stopped the action before the 11th round.
The victory at the Desert Diamond Arena in Glendale, Arizona was the 40th of Navarrete's 43-fight career, while Nunez's 19-bout win streak came to an end.
"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 controlled the action in the early rounds before landing some damaging shots in round nine, forcing the doctor to take a look at Nunez for the first time.
Following another dominant display from three-weight world champion Navarette in round 10, Nunez was deemed unable to continue after sporting a bloodied face and a severely swollen right eye.
WBC super-featherweight champion O'Shaquie Foster and WBA title holder Lamont Roach are potential options for Navarrete to face next.