The 26-year-old Charlo knocked Williams down three times in the much-anticipated fight en route to a fifth round TKO.
The 26-year-old Charlo knocked Williams down three times in the much-anticipated fight en route to a fifth round TKO that improved his record to 25-0, with 19 knockouts.
He sent Williams to the canvas with a punishing right uppercut with 80 seconds left in the fifth round then finished him off with a left hook 26 seconds later.
Williams also got knocked down by a stinging jab in the second round but got up quickly from that one. He boxed well in rounds three and four before getting careless in the fifth when he walked into an uppercut that sent him crashing to the floor of the Galen Center arena at the University of Southern California.
After the fight Charlo refused to shake hands with Williams which attracted boos from the crowd and sparked a yelling match between the two corners.
"I told him 'I want your apology, I don't want your congratulations'," Charlo said, furious at Williams' pre-fight trash-talk.
"I never disrespected the dude until I knocked him out," Charlo said.
Despite the three knockdowns, the fight proved to be one of the toughest tests of the career of the unbeaten champion.
Williams, 26, suffered the first defeat of his career as he dropped to 22-1-1 with 14 knockouts.
This was a fight many boxing fans had anxiously awaited since Williams became the mandatory No. 1 challenger in March after knocking out Marcello Matano in the seventh round of a title eliminator.