LOS ANGELES (AFP) — Saul "Canelo" Alvarez reaffirmed his super middleweight supremacy on Saturday with a devastating unanimous-decision victory over Jermell Charlo to retain his undisputed world title.

In a battle of undisputed champions, Mexico's Alvarez knocked down Charlo in the seventh round as he defended his World Boxing Organization, World Boxing Council, World Boxing Association and International Boxing Federation belts, becoming the first to defend all four for a third straight time.

Judges Max DeLuca and David Sutherland scored it 118-109 and Steve Weisfeld saw it 119-108 for Alvarez, who was the aggressor from the start.

He sent Charlo, the undisputed super welterweight world champion, to the canvas for just the second time in his career in the seventh, rocking him with a right to the temple then following up with an uppercut that had the American sagging to a knee.

"You know, I worked all the fight to go in the body," Alvarez said. "And then I changed the punch and that's what happened."

Alvarez said he'd planned to attack Charlo's body, and he went after it early, digging in from the right and left.

"We worked for that, we worked to work in the body," Alvarez said. "We know he's a great fighter. He knows how to move in the ring and we worked that in the gym for three months."