Max Holloway knocks out Justin Gaethje with the last punch of the fight at UFC 300

Max Holloway scored a brutal one-punch knockout to beat Justin Gaethje to win the BMF title at UFC 300.

Holloway was seemingly cruising to a decision victory until he decided to throw down with Gaethje in the closing stages of their BMF showdown.

After pointing to the ground, Holloway and Gaethje exchanged leather before the fight came to an abrupt end.

The Hawaiian connected with a massive overhand-right that landed flush on Gaethje's chin, which immediately slept his opponent.

On commentary, Joe Rogan called it the greatest knockout of all time as he praised Holloway's masterful performance inside the Octagon.

He's in line to pocket a massive $300,000 Performance of the Night bonus after Dana White increased the bonuses at the pre-fight press conference.

Speaking to Rogan inside the Octagon, Holloway called out UFC champions Ilia Topuria and Islam Makhachev.

"'El Matador' [Ilia Topuria] he is running from the bull at 145," he said. "Tell him to sign the contract. Islam [Makhachev] is famous for defending against [featherweights] right? I’m him. I’m right here!

"Any weight, I’m gladiator. I don’t care, whoever’s next sign the dotted line."