Nonito Donaire rounded out a fantastic year by stopping Jorge Arce in the third round of their WBO super-bantamweight title fight in Houston.
Donaire, the Filipino heir-apparent to Manny Pacquiao, stepped up a division to win the belt at the start of 2012 and has now successfully defended it three times.
The 30-year-old landed a left hook to the chin of the veteran Mexican late in the third to end the fight and ultimately send Arce - himself a five weight champion - into retirement.
"My career is over. I'm leaving after losing to the best man," said Arce, whose finally tally reads 61-7-2. "He is very good. He has power. He can finish the fight at any moment.
"I promised my family if I lost I would leave. I retire to go home and watch the fights on TV."
Donaire (31-1), who has not lost since his second fight 11 years ago, had already flattened his opponent twice in the second round - first with a straight right hand and then a couple of left hooks.
"I went out and pretty much timed him," he said. "We wanted to slow him down and get him thinking he could get in there. We knew he would open up.
"I've never really gone and hit with the left hook, but I knew I was going to go out there and give it everything, no matter what."
Donaire, a champion in four weight classes, is still seeking a unification fight with WBC champion Abner Mares, who is under a different promotional banner.