Filipino champion Nonito Donaire stopped Toshiaki Nishioka in the ninth round in Los Angeles to defend his WBO super-bantamweight title.
Donaire, 29, knocked his Japanese opponent down for the second time in the fight at 1:54 of round nine and, although Nishioka got up, his corner stepped in to end the fight.
It was a 29th victory in a row for Donaire, who retained his WBO and IBF super bantamweight crowns and handed veteran Nishioka his first loss in eight years.
Donaire dominated proceedings at the Home Depot Centre, keeping Nishioka at distance with left jabs and rights to the body.
He put his man down for the first time with two successive left hands inside with a minute left in the sixth round and then ended the contest when Nishioka walked onto a straight right hand in the ninth.
Donaire said: "We wanted to use my jab and use my speed. I wanted to open him up by timing that jab.
"When you engage you open him up and then the demolition man comes in to knock him out. I got the guy that I thought was best in the division."
Meanwhile, Brandon Rios stopped the previously unbeaten Mike Alvarado in the seventh round of a barn-storming WBO light-welterweight eliminator.
With the fight in the balance, Rios (31-0-1) landed with a big right hand towards the end of round six and blasted him away in the next to earn a possible shot at Manny Pacquiao in the New Year.