Conor McGregor finished Donald 'Cowboy' Cerrone just 40 seconds into the first round of their welterweight bout at UFC 246 in Las Vegas.
Only seconds into the fight, McGregor hurt Cerrone with his shoulder while in a clinch. Those blows badly damaged Cerrone's nose.
McGregor soon landed a high kick to the 36-year-old's head which stunned Cerrone. As McGregor continued to land punches with Cerrone lying against the cage, referee Herb Dean stepped in to stop the fight.
"I changed levels with it and came up into it, it was a good shot," said McGregor of the blows which hurt Cerrone's nose.
"Donald holds the record for the most head kick knockouts. I'm so happy to be able to get him down with a head kick.
"My team has been phenomenal, the work has been phenomenal, the people have been phenomenal."
Cerrone, who was later transported to hospital, said after the fight:
"I'd never seen anything like that.
"He threw me way off guard; he busted my nose, it started bleeding then he stepped back and head kicked me. Oh man, this happened fast, I got my ass whipped early."
The fight was McGregor's first since his October 2018 defeat to Khabib Nurmagomedov.
Cerrone went into the bout on a two-fight losing streak. He was stopped by Tony Ferguson in June of last year and Justin Gaethje in September.
— ESPN MMA (@espnmma) January 19, 2020