Year 2013 has been a great year so far for us UFC fans. This year, we witnessed some of the greatest triumphs and upsets in the Octagon and also became astonished and surprised to some of the most brutal knockouts in UFC history.

Although it is still early to announce the Knockout of the Year award, as there are great matchups in the coming months with KO of the year potential, it is pretty much exiting to roundup the top five knockouts in the UFC so far.

I've included in the list some of my personal choices for KO of the year. Each has all the potential to be named as the best this year. For the list, I based their rankings on fight importance, audience impact and technique used. I also included some videos for our viewing pleasure.

Wanderlei Silva Knockouts Brian Stann

Silva has made a career from knocking out opponents in the most brutal way possible, ending 25 of his 35 career wins via KO. Stann also has several exciting knockout victories in the UFC with nine KO wins. That's why when these two were scheduled to fight at UFC on Fuel TV in March, there was a feeling that a fight knockout is inevitable.

And that had been the case for these two. Silva, although seen by many as the underdog in the match due to his age, managed to land a ferocious two-punch combination that floored Stann and followed it vicious ground and pound that signaled the referee to stop the fight.

With the win, Silva has proved that he still is a force to be reckoned with in the very talented middleweight division.

Anthony Pettis Knockouts Donald Cerrone

Pettis is well-known for his highlight reel kicks and their accuracy. In his matchup against the very durable Cerrone, who has never been knocked out in his MMA career prior to the fight, he used his kicking prowess to score a stoppage.

Pettis landed a left kick to the liver of his opponent, who crumpled to the ground in pain after the shot. The KO has proven how dangerous Pettis can be in standup exchanges and that he is the number one contender for the UFC lightweight championship strap, currently being held by his arch nemesis Benson Henderson.

Vitor Belfort Knockouts Michael Bisping

Prior to his fight with Belfort, the English mixed martial artist Bisping was being considered as the next challenger to the then middleweight champ Anderson Silva. But the Brazilian spoiled this opportunity when he stopped Bisping via head kick in the second round.

With the win, the Brazilian improved his ranking to contender status and proved that he deserved a second shot for the UFC middleweight title.

Belfort has a total of 16 knockout victories in his career. He debuted in the UFC in 1997 and won his first three fights via knockout, thus being dubbed as "The Phenom."

Antonio Silva Knockouts Alistair Overeem

There had been a series of back-and-forth trash talks between the two prior to their fight. This had caused the underdog Silva to think that the favorite Overeem, who seemed to worry more of his next fight than his current matchup, was taking him lightly and disrespecting him.

Thus, when the Brazilian managed to land an uppercut to his opponent's chin, he wasted no time and unleashed his anger toward Overeem with forceful combinations that drove his opponent out of his consciousness. It looked like Silva won't stop punching his opponent until he asks for mercy. Even referee Herb Dean found it hard to stop the furious Silva from hurting his opponent.

The win is dubbed by many as the biggest win in Silva's career, considering the level of competition he has faced in Overeem, who has held championship belts in Strikeforce, Dream and K-1.

Chris Weidman Knockouts Anderson Silva

This one top the list simply based on the level of competition Weidman has faced in Silva who was then then number one pound-for-pound fighter in MMA rankings and considered by many as the best fighter in the history of the sport.

Silva's style of fighting includes several feints to ploy his opponent into attacking him so he can land his knockout punch. This trick has proven to be effective all throughout the Brazilian's MMA career, wherein he scored 20 knockouts. Nonetheless, Weidman has proven that he has enough torque in his hands to stop the seemingly indestructible Silva, who held the middleweight strap for eight years prior to their fight.

Weidman scored the knockout win against Silva and won the UFC middleweight title in the most exciting way possible.