Duddy was suffering his second defeat in his 31 career professional bouts
Middleweight John Duddy's hopes of a world title shot suffered a huge blow when he was unanimously outpointed by Julio Cesar Chavez Jr on Saturday.
Unbeaten Chavez Jr took control from the early stages of the bout although Duddy did push the Mexican to 12 rounds for the first time in his career.
Derry man Duddy was suffering his second defeat in his 31-fight career.
Duddy did wobble Chavez in the sixth but the Mexican won 120-108, 117-111 and 116-112 on the scorecards.
"John is the toughest fighter I've faced so far. He kept the pressure on and really pushed me," said Chavez.
"But I knew coming in that he was going to be challenging, and I was happy to walk away with the victory."
The Mexican's legendary father Julio Cesar Chavez led his son into the ring at the start of the fight in San Antonio.
The fight was Chavez's first since 10-round unanimous decision over Troy Rowlands in November that was changed to a no-contest after the Mexican tested positive for a banned substance.
Chavez was suspended for seven months by the Nevada State Athletic Commission after the diuretic was detected in the post-fight drugs test.
Saturday's fight also was Chavez's first with trainer Freddie Roach, who guides WBO welterweight champion Manny Pacquiao.