VIDEO: Celebrating the 4th Anniversary of Conor McGregor Knocking Out Jose Aldo in 13 Seconds

Before he started fighting old men in bars and smashing fans' cell phones in Miami, Conor McGregor was the most famous face in mixed martial arts-- and the most famous left hook, too. That was no longer up for debate when he stepped into the Octagon against featherweight champion Jose Aldo in the main event at UFC 194 in Las Vegas. With the belt on the line, the Notorious MMA delivered one of the most iconic, stunning knockouts in UFC history. And it only took 13 seconds.

Just. Like. That.

Aldo was the beginning, middle, and end of the featherweight GOAT conversation heading into the event, having defended his title seven times during his undefeated run in UFC. With one mighty left, McGregor changed all that in an instant, sending Aldo on a downslope that now finds him looking to recreate himself in the bantamweight division.

And for McGregor, the moment signaled that he was, for all his bluster and talking out of turn, on a meteoric rise.

Conor went on to win the lightweight title as well, becoming the first UFC fighter ever to hold championships in two weight divisions at the same time. His fall from grace would come around at the hands of Khabib Nurmagomedov last October, but that shouldn't take a single thing away from the incredible KO masterstroke he delivered four years ago today.

Sheesh, what a left he's got.