The 31-year-old Irishman stopped his American opponent with a punch to the nose swiftly followed by left kick to the head, it was all over in just 40 seconds.
Flooring Cerrone, McGregor then finished the fight on the floor, to the delight of the sell-out crowd in Las Vegas. Speaking after the fight, McGregor said: “I feel really good, and I came out of here unscathed. I’m in shape. We’ve got work to do to get back to where I was.”
The Irish former two-division champion had walked to the cage wearing the Irish flag.
Following his defeat, Cerrone said: “I’d never seen anything like that. He busted my nose, it started bleeding, and he stepped back and head-kicked me. Oh, man. This happened this fast?”
Despite previous shows of unsportsmanlike conduct, McGregor spoke to Cerrone after the bout, and even hugged his opponent’s grandmother when she entered the octagon to hug her defeated grandson.