Watch David Lemieux's spectacular one-punch KO over Gary O'Sullivan

Watch Canada's David Lemieux's spectacular one-punch KO over Spike O'Sullivan during their middleweight clash at the undercard of GGG vs Canelo 2 at the T-Mobile Arena, Las Vegas, Nevada.

Lemieux caught O'Sullivan in the very first round with a counter left hook that lands right on the pipe. O'Sullivan went down for good. The referee stopped the fight as O'Sullivan in no position to continue. Official time of the stoppage: 2:44 mark in the first round.

With all the trash talking leading into the fight, it was nice to see the fighters hug each other after the fight.