Kiwi UFC star Carlos Ulberg KOs opponent in just 12 seconds: 'What a freaking beast'

Kiwi knockout artist Carlos Ulberg needed just 12 seconds to finish his UFC fight on Sunday, producing a stunning KO of Alonzo Menifield that will go down in the record books.

Ulberg, 33, continued his winning steak in the Octagon at UFC St. Louis on Sunday with a big left hand.

Menifield came out aggressive and tried to overwhelm Ulberg in the opening seconds of round one, but the New Zealander was ready and avoided the blitz.

Ulberg countered with shots of his own and quickly had his opponent hurt. Menifield seemed to recover momentarily before Ulberg finished the fight with a left hand.

The win was the third fastest in the history of the 205-pound division, and Ulberg was relieved it was over. 

'We knew coming up against a guy like Alonzo Menifield to be worried about his power - he does have a lot of power,' Ulberg said post fight.

'As long as I stuck to the game plan with my coaches - we knew he was gonna come forward. We did expect something like that, he did catch me and that wo ke me up.

'When you wake a lion up, he comes out. 

'Anybody in that top 10, I'll destroy anybody in my way.'

Fans and pundits were shocked by the display from Ulberg, who is now undefeated in his last six outings.

'Holy smokes Carlos Ulberg! What a freaking beast,' posted Ariel Helwani to X.

Ulberg, who will be looking for ranked opponents from here on, used to work as a male model and stripper before embarking on his career as a prize fighter.

Ulberg appeared on reality TV show Game of Bros in 2018 and was offered a spot on The Bachelor twice - but it wasn't for him.

'I've been a practical person my whole life, and I enjoy the thrill of getting punched in the face or delivering a few punches,' Ulberg told Daily Mail Australia.

'It's a good challenge – I love the challenge of the sport and what it gives me. It gives me satisfaction and discipline.'

Ulberg goes by the name of 'Black Jag' when he fights in the octagon - but when he started off fighting he was known as 'Ladies' Night' for a very good reason.

'That was when I was doing ladies' nights in Australia,' explained Ulberg. 'Hosting parties, hosting club nights – I guess it transferred over to my fight career. But it was given to me by an announcer in New Zealand.

'I had it for my very first fight, but then I wanted to change it up. So, I changed it to "Black Jag".'