The 10 Nastiest MMA Knockouts

B.J. Penn vs Caol Uno, UFC, 2001

One of the UFC’s most dominant lightweights, B.J. Penn went from the world of jiu-jitsu to the Octagon with ease. Although he was famed for his grappling skills, he also could get it done with his fists if necessary. Case in point: his victory over Caol Uno at UFC 34 in Las Vegas. The agile Japanese fighter Uno went after Penn with a flying kick, only to be rebuffed by Penn, who then bulled Uno into the fence and started landing disgusting punches right to his face, knocking him out in just 11 seconds. The lightning-quick match made Penn a star and left Uno looking shattered.

Mirko “Cro Cop” Filipovic vs Igor Vovchanchyn, PRIDE, 2003

In his prime, Igor Vovchanchyn was one of MMA’s most terrifying forces, ripping through the competition all over the world. Starting in his native Ukraine, he went on to dominate in Russia and Brazil before winding up in Japan’s PRIDE outfit. In the early part of the 21st century, his career started to decline, but the moment that really ended it for him was his horrific KO loss to the equally scary Mirko Filipovic. A minute and a half into the fight, Cro Cop delivered one of his trademark roundhouse kicks to Igor’s head, dropping him like a sack of potatoes.

Dan Henderson vs Michael Bisping, UFC, 2009

During the filming of "The Ultimate Fighter" season nine, a lot of bad emotions came up between coaches Dan Henderson and Michael Bisping. So naturally, Dana White put the two in the cage at the epic UFC 100 show in Las Vegas. Bisping had a stellar record, having never been knocked out in his entire MMA career, but Henderson proved he had what it took. In the second round, he connected with an absolutely earth-shattering right hook to Bisping’s jaw that instantly removed him from the land of the living, and then followed it up with an elbow drop for good measure. Most observers considered it the absolute best KO of all of 2009.

Jose Aldo vs Cub Swanson, WEC, 2009

Very often, nasty knockouts happen early in a fight when the warriors are still feeling each other out. It’s easier to sneak in a big move then that will put you down for the count. One of the most impressive early-minute knockouts we’ve ever seen came at WEC 41, where rising star Jose Aldo was matched up with Cub Swanson in a tournament for the Featherweight title. Just eight seconds into the fight, Aldo launched himself at Swanson with a grotesque double flying knee that sent Cub crumpling to the mat, unable to defend himself against a flurry of punches.

Junior dos Santos vs Fabricio Werdum, UFC, 2008

One of the ingredients to a truly awesome knockout is often the element of surprise. It’s only possible to scout a matchup so much, and when newcomer Junior dos Santos stepped into the Octagon in his UFC debut against top Heavyweight contender Fabricio Werdum, nobody thought he had much of a chance. They were wrong, though – just a minute and a half into the match, dos Santos unleashed one of the sickest uppercuts the UFC has ever seen, taking Werdum off his feet and out of consciousness, instantly making him a star.

Vitor Belfort vs Matt Lindland, Affliction, 2009

The Affliction MMA promotion was a short-lived attempt to compete with the UFC, but it did bring us at least one unforgettable knockout when Brazilian striker Vitor Belfort faced off against Matt Lindland in 2009. This was a long-awaited fight that was postponed several times, and all that waiting didn’t do wonders for Belfort’s temper. Just seconds into the fight, Vitor clocked Lindland with an incredible left to the jaw and followed up with four brutal shots on the ground before the ref pulled him away. The footage of an unconscious Lindland convulsing uncontrollably on the ground is difficult to watch.

Lyoto Machida vs Rashad Evans, UFC, 2009

Going into UFC 98, Rashad Evans was the UFC’s golden boy. After winning the second season of "The Ultimate Fighter," he’d become one of the promotion’s best fighters, never losing a match on his way to seizing the Light Heavyweight belt from Forrest Griffin. He was originally slated to defend the belt against Quinton “Rampage” Jackson in Las Vegas, but injuries forced Jackson to withdraw and be replaced by Brazilian Lyoto Machida, who was also undefeated. One record would have to be shattered, and it was Evans who took the fall. Machida landed a series of sharp punches in the second round that sent Evans to the mat and to dreamland.

Gary Goodridge vs Paul Herrera, UFC, 1996

The early days of the UFC were kind of anarchy, with no weight divisions leading to some severely unbalanced matches. One of the nastiest was the bout between boxer and martial artist Gary Goodridge and wrestler Paul Herrera at UFC 8. Goodridge outweighed his opponent by more than 80 pounds and it showed. The larger man trapped Herrera in a crucifix hold, immobilizing both of his arms and making it impossible for him to defend his poor face, which Goodridge proceeded to rain elbows down on in a sickening display of brutality. It took six years for the bones in Herrera’s face to heal.