5. Conor McGregor vs. Jose Aldo
UFC 194 “Aldo vs. McGregor”
Dec. 12, 2015 | Las Vegas
When a terrific knockout occurs, fans and media typically overreact and rush to label it the “greatest,” seemingly oblivious to all others that had come before it. In the case of McGregor’s 13-second destruction of Aldo, there is not enough hyperbole to describe it.

The anticipation for the fight was surreal, as it took longer than expected to materialize because of an injury to the Brazilian. The two engaged in months of hateful trash talk, bringing their rivalry to a boil. McGregor predicted the Brazilian would crumble as soon as he was hit clean, and the Irishman vowed to take out Aldo inside one round. He was right.

Aldo came out of his corner looking anxious. He leaned in too far and overextended on a right hand. McGregor was waiting for him. He saw it coming and delivered a short left hook that dropped Aldo at his feet. The longtime champion was done, but McGregor delivered two hammerfists for good measure that left Aldo with a gash across the bridge of his nose. Never before had a UFC championship changed hands so quickly.

Number 4 » Diaz vs. Lawler