There are so many ways one can win a mixed martial arts contest, but a knockout is undeniable. In 2015, there were 474 total UFC fights and 154 of them ended with a knockout or TKO.
Here’s a look back at the best UFC knockouts from the year that was.
Conor McGregor vs. Jose Aldo
All the promotion, all the trash talk, all the anticipation, yet nothing could have prepared fight fans for what went down in the UFC 194 main event. McGregor knocked Aldo out in 13 seconds. Even the most staunch McGregor supporter would have looked at you sideways if you predicted that outcome. The counter-left hand the Irishman landed was perfection. Anyone who calls this a “lucky punch” doesn’t know what they’re looking at. Aldo, one of the greatest UFC champions and mixed marital artists of all time, made fundamental mistake. He charged in, loaded up on his right hand, left his chin exposed and McGregor pulled the trigger.
“Nobody can take that left hand shot,” McGregor said after the fight. “He’s powerful and he’s fast, but precision beats power and timing beats speed and that’s what you saw there.”
Holly Holm vs. Ronda Rousey
Back in November, I wrote about exactly what Holm did to beat Rousey. It certainly wasn't as simple as "she kicked her in the face," although that's how the fight ultimately ended. Holm picked apart Rousey with her hands and unleashed a kick early in the second round at UFC 193 that sent the sports world into a frenzy.
Uriah Hall vs. Gegard Mousasi
Following a first round that saw Mousasi dominate the action on the ground and nearly earn a submission win, Hall came out in the second frame and proved why he's regarded as one of the most dangerous and creative strikers in the UFC.
Paul Felder vs. Danny Castillo
Felder's 2014 UFC debut was a split decision against Canadian Jason Saggo but he really put himself on the map with this spinning back fist at UFC 182.
Thiago Santos vs. Steve Bosse
This is a fight that honestly should never have been sanctioned. Santos is a legitimate, rising contender in the middleweight division while Bosse, a former hockey enforcer, hadn't fought in two years and had never faced UFC-calibre competition.
Thomas Almeida vs. Yves Jabouin/Brad Pickett/Anthony Birchak
Not many fighters had the year Almeida did. He picked up highlight-reel KO wins against Jabouin, Pickett and Birchak.
Frank Mir vs. Todd Duffee
This fight was 73 seconds of heavyweight chaos. Both men -- especially Duffee -- threw caution to the wind and looked for a quick KO. Duffee kept his hands recklessly low and Mir capitalized.
Stephen Thompson vs, Jake Ellenberger
Georges St-Pierre has said Thompson is the best striker he ever trained with and his wide array of techniques were on full display against Ellenberger.
Ronda Rousey vs. Bethe Correia
This was the first fight in Rousey's career that she displayed true knockout power. The technique from both ladies was lacking but Rousey connected flush.
Dominique Steele vs. Dong Hyun Kim
You don't see slam knockouts often in the UFC, but Steele put Kim away with this one at the UFC's debut event in South Korea.
Tom Lawlor def. Gian Villante
In his return to the light-heavyweight division and his first fight in nearly 28 months, Lawlor slipped a Villante jab and came over the top with a perfect counter-right hand.
Frankie Edgar vs Chad Mendes
The former lightweight champion put Mendes away with a combo that culminated in a left hook to the nose. This win potentially earned Edgar a shot at McGregor's featherweight belt in 2016.
Fredy Serrano vs. Bentley Syler
The former Olympic wrestler dipped his head like he was about to throw an overhand right but threw an uppercut instead. Syler was out before he hit the ground and Serrano looks like he has the potential to become a bantamweight contender.
A pair of 8-second KOs
Makwan Amirkhani stopped Andy Ogle with a flying knee and punches, while Leon Edwards did the same to Seth Baczynski...minus the knee.
Yoel Romero vs. Lyoto Machida
The Olympic silver medallist cemented himself as a contender at 185 pounds when he finished Machida with some of the most brutal ground-and-pound elbows you'll see in MMA.
Honourable mention: Matt Dwyer def. William Macario, Jeremy Stephens def. Dennis Bermudez, Dan Henderson def. Tim Boetsch, Ross Pearson def. Sam Stout, Sam Alvey def. Cezar Ferreira, Ryan Benoit def. Sergio Pettis, Alistair Overeem def. Junior dos Santos