John Duddy lost only the second fight of his 31-fight career on Saturday night as he was unanimously outpointed by Julio Cesar Chavez Jr.
The Derry man pushed his Mexican opponent to 12 rounds in San Antonio but his hopes of a world title shot now lie in tatters.
"John is the toughest fighter I've faced so far," the unbeaten Chavez remarked.
"He kept the pressure on and really pushed me.
"But I knew coming in that he was going to be challenging, and I was happy to walk away with the victory."
The fight was Chavez's first since his 10-round unanimous decision over Troy Rowlands in November was changed to a no-contest after the Mexican tested positive for a banned substance.