For as much as we think know, we really don't know jack. Before every sporting event ever, fans, media and their grandmothers will make a prediction on the result of a match. It's human nature for us to speculate and gossip on who will come out victorous simply because it's fun to do. No matter how much knowledge one may have, no one ever really knows for sure.

This past Sunday night, Dennis Siver had the potential to crush the hopes of all of Ireland if he could have defeated the notorious Conor McGregor. The entire promotional story of this fight was just how incredible McGregor was and Siver was treated as just a body that was in McGregor's way, and he was going to crush it en route to a title shot. Alas, the court jester smashed the Russian born Siver with a second round TKO and we were denied an upset for the ages.

While Siver couldn't pull off the upset, it did get us thinking about the greatest upsets in MMA history. In the sport's short existence we have seen several fights end with a man who was given no chance of victory prior to the bout yet ended with that same fighter having his arm raised in victory. An upset could shock you, but a great upset makes you speechless. The ranking of the list is not determined by which fights had the largest betting odds though.  Rather, this list is more about which upsets were the most shocking, the most emphatic and the most emotionally thrilling. I repeat, this list is NOT taking into account betting odds. Now don't get upset with me as I present the top upsets in Mixed Martial Arts history.

11 11. B.J. Penn vs. Frankie Edgar - UFC 112

Frankie Edgar was the demon not named Georges St-Pierre that B.J. Penn could not get off his back during his career. They met three times and each time, "The Prodigy" failed to find an answer to well, The Answer. People forget that things weren't supposed to be this way when they first met in Abu Dhabi at UFC 112. Penn entered this fight as the UFC Lightweight champion, fresh off his third title defence over Diego Sanchez in which he massacred "The Nightmare" for five rounds until he opened a gaping hole on Sanchez' head with a head kick. He became the greatest lightweight ever and looked to continue his legacy with a win over Edgar.

On the other hand, the number one contender Edgar earned his title shot with a win over Matt Veach. Yeah, people did not like the Jeresy kid's chances but he said screw them and went after Penn like no lightweight had since Jens Pulver. Penn was peppered with quick strikes and flustered by the constant movement of the challenger which led him to lose his championship via unanimous decision. The reason this upset is so low on the list is that you can make a strong case that Penn was robbed by the judges (how the hell did a judge score it 50-45 for Edgar?) as Penn landed plenty of hard counter punches and defended 12 of 13 takedown attempts from Edgar. Nonetheless, Edgar shocked the world and walked out of United Arab Emirates with the UFC championship.

10 10. Joe Lauzon vs. Jens Pulver - UFC 63

Not only was this a huge upset, but it was an awkward one as well. For the fifth season of The Ultimate Fighter, Jens Pulver was set to coach vs B.J. Penn then fight him in a rematch of their 2002 Lightweight Championship match. Prior to their coaching duties, Pulver fought off against unknown prospect Joe Lauzon, seemingly as a warm up matchup for Pulver to show off to the UFC audience.

As plans will be they will go awry though because Lauzon wasn't interested in being a stepping stone. Lauzon instead rushed the original Lightweight champion with a takedown and a barrage of strikes out of the opening bell and knocked Pulver out in less than a minute. The upset was bad enough, but what's even funnier is that Lauzon ended up being on the same show that Pulver was coaching in a few months! If you were wondering, Pulver did not pick Lauzon on his team.

9 9. Chris Weidman vs. Anderson Silva - UFC 162

Surprised this is only number eight? I understand. (Anderson Silva voice) it's normal. Yes, Anderson Silva was considered by many to be the pound for pound best fighter of all time heading into this fight and Chris Weidman was a largely unproven prospect with a scant 9-0 record but many pundits saw Weidman winning. His combination of powerful wrestling, technical grappling and mental fortitude was thought to be the perfect combo to squash the Spider. What people didn't see coming was a man with no formal striking background knocking out Silva with a picture perfect left hook while Silva was clowning around with his hands at his waist. That iconic image of an unconscious Silva being bounced on his head by Weidman's fist is a picture that has been burned in every MMA fan's mind for eternity.

8 8. Tito Ortiz vs. Ryan Bader - UFC 132

It seemed laughable then and it still seems laughable now. How in the hell did Tito Ortiz stand a chance against the hulking All-American wrestler from Arizona State named Ryan "Darth" Bader? Quite literally every skill that Ortiz had at one point in time Bader did better. In the striking department Bader had power in his stand up attack that Ortiz could only dream about. When it came to grappling, Bader seemed to have a much more explosive takedown game while Ortiz seemed old and out of touch. Hell, Ortiz's last win came against a WAY over the hill Ken Shamrock.

There was no chance a young stud like Bader could lose to old man Tito... but he did. With his UFC career most probably on the line, Ortiz floored Bader with a right uppercut and jumped on the dazed to tap him out with a guillotine. The win saved Ortiz's UFC run and set Ryan Bader way in back of the line for a title shot that was so close yet so far.

7 7. Rameau Sokoudjou vs. Antonio Rogerio Nogueira - PRIDE 33

The career of Sokoudjou is one of the most curious cases in MMA. Coming into the sport as a second dan black belt in Judo one would expect him to be a strong top grappler with vicious takedowns but instead he made his name on the back of two astounding knockouts. One of them was a (consider it an honourable mention) first round knockout of one of the more forgotten but still excellent light heavyweights in history by the name of Ricardo Arona. The first knockout though, was sheer madness.

In his PRIDE debut, Sokoudjou knocked out one of the biggest legends in the promotion's history, Antonio Rogerio Nogueira. The same Nogueira brother who submitted Dan Henderson and gave Shogun Rua the fight of his life in the PRIDE Middleweight (203 lbs) Grand Prix was now being knocked out by a mystery judoka. Sokoudjou can now be seen in Bellator beating up prestigious names like Malik Merad.

6 6. Forrest Griffin vs. Shogun Rua - UFC 76

They year of 2007 was known as the year of the upset in MMA for good reason. Five entries on this countdown happened in that year and this one was the final shell shock. After the PRIDE promotion folded, there was no other fighter who came into the UFC with more hype than Mauricio Shogun Rua. The Brazilian buzz saw ran wild over the promotion with an essentially undefeated record and won the 2005 PRIDE Middleweight Grand Prix, defeating Quinton Jackson, Antonio Rogerio Nogueira, Alistair Overeem and Ricardo Arona to do it. Shogun was expected to capture the UFC title in short order after his debut vs tough as nails but not too skilled Forrest Griffin.

People waited with baited breath for Shogun to kick Griffin's head into the bleachers but it didn't happen. Instead the match became more of a grappling match with both men taking the other down sprinkled with brief striking exchanges. Griffin kept his pace though as Rua started to falter, and with less than 20 seconds remaining in the fight Griffin sunk a rear naked choke and defeated the pride of PRIDE. Griffin would use this momentum to defeat Rampage Jackson for the UFC Light Heavyweight Championship. Amazing.

5 5. Fabricio Werdum vs. Fedor Emelianenko - Strikeforce: Werdum vs Fedor

Even the greatest of conquerers fall. When Fedor Emelianenko signed with Strikeforce in 2010, fans rejoiced as the U.S. audience would see first hand just how devastating "The Last Emperor" could be. After starching Brett Rogers with an overhand right, it seemed that Fedor would just need to beat Fabricio Werdum to get to kickboxing powerhouse Alistair Overeem's Strikeforce heavyweight championship.

In his reckless pursuit of gold, Emelianenko made a tremendous lapse of judgment whilst fighting Werdum. After knocking Werdum down in the opening minute, Fedor jumped into the guard of a BJJ world champion with little regard for submission defence, throwing down punches like no tomorrow. In his smashing of Werdum's face, Fedor left one of his arms down for "Vai Cavalo" to grab. Big mistake. Werdum grabbed Fedor's arm, dragged it across his body, wrapped up a triangle choke and submitted the greatest heavyweight the sport has ever seen in a little over a minute. Fedor would never be the same and Werdum would go on to become the current UFC Interim Heavyweight Champion.

4 4. Gabriel Gonzaga vs Mirko Cro Cop - UFC 70

Another upset in the year 2007, and this one was definitely the most violent. Another PRIDE legend coming into the UFC, Mirko Cro Cop was expected to steam roll over his opponents until he would eventually face the UFC Heavyweight champion Randy Couture. That match would have definitely been one of the most anticipated title fights in UFC history. Unfortunately for the UFC brass, Gabriel Gonzaga wanted a title shot too. In a number one contender match, the Brazilian Jiu-Jitsu world champion Gonzaga fought the kickboxing terror Cro Cop but nobody saw the finish coming. After only one round, Gonzaga threw a high kick from hell to the temple of Cro Cop and it crumbled the former PRIDE Open Weight Grand Prix winner in a heap. The dream match was dead, and Gonzaga stamped his place as the number one contender with authority.

3 2. Randy Couture vs. Tim Sylvia - UFC 68

Fun fact: this is my favourite fight in MMA history. I think anybody who watched this fight would understand why this fight carries so much emotional weight. Couture's entire career is based on defying the odds and this was no exception. After losing to Chuck Liddell for a second straight time in 2006, Couture walked away from the sport. As he transitioned to the commentary booth for UFC PPVs, it seemed that the desire to fight was still there for Couture.

A reinvigorated Couture would make his return in the heavyweight division and the challenger to the 6-foot-8 265 pound Goliath champion Tim Sylvia. Everything was against Couture from size to striking and most importantly age. You wouldn't guess that from watching the fight though because Couture channeled his teammate Dan Henderson's H-Bomb to drop Sylvia in the opening seconds of the fight. For the next four rounds Couture would out-strike, out-wrestle and out-pace a man 11 years his junior. Couture captured the Heavyweight championship at age 43 and shocked the world just like he did so many times in his career. As Couture said it himself, "Not bad for an old man".

2 2. Holly Holm vs. Ronda Rousey - UFC 193

Ronda Rousey was seen as invincible throughout her MMA career. She had never lost a fight, or even a single round, as she tore through fighter after fighter. It was her dominance and high profile in the sport that convinced the UFC to introduce a women's division. Rousey was named the Women's Bantamweight Champion by the UFC back in 2012. Coming into her UFC 193 bout with Holly Holm, Rousey was 12-0 in her MMA career, with six successful title defenses. Along came Holly.

Holly Holm was unlike what Rousey had seen before. She had a solid boxing pedigree, along with kickboxing, with a style that would create problems for the judoka. Sure enough, that's what the undefeated challenger did. Holm made Rousey look like an amateur, tagging her with quick strikes, with the champion left swinging and missing. She took Rousey completely out of her element, keeping the fight upright. After a dominant first round by Holm, it was more of the same in the second round, as Rousey missed wildly with a strike, only to lead to a vicious head kick by Holm which knocked Rousey to the canvas. Holm followed with some punches and it was all over. The dominance of Rousey had ended.

We'll see how Rousey rebounds from this, given all the distractions she had to deal with in the fight. Her coach had declared bankruptcy, her mother was outspoken against him, her family didn't attend her fight, her boyfriend has been accused of abusing his ex-wife and Rousey was all over the place all year. Whatever the case, Holm shocked the world and this stands as one of the biggest upsets in the history of the sport.

1 1. Georges St-Pierre vs. Matt Serra - UFC 69

Here we go again... In the year 2007, an upset of monumental proportions would occur at UFC 69. The champion is a babyfaced, polite French-Canadian Georges St-Pierre who is fresh off a win over the best welterweight ever Matt Hughes at UFC 65. St-Pierre is thought by many to be the man who will dominate the welterweight division for years to come.

The challenger, on the other hand, is a chubby, stumpy Italian-American from New York named Matt Serra. While St-Pierre looks to be chiseled out of granite, Serra has a pedestrian physique to go along with his pedestrian record of 9-4. Serra earned his title shot by eeking out a boring split decision win over a man is incapable of having a boring fight in Chris Lytle. Needless to say, nobody gave Serra a prayer's chance in defeating the future of the UFC.

St-Pierre was the future of the UFC, but Serra was the present. The challenger went to work on the champion with body punches and countering the champion's strikes. Then it happened. Serra landed an overhand right which put "Rush" on spaghetti legs but didn't quite put him down. As GSP tried to fight back in vain, Serra punished him for his tactical error and punched St-Pierre until he dropped. Once he was mounted, GSP lost his will to fight and tapped out a second after the referee pulled Serra off of him. The result was shocking, violent, demoralizing to the loser and astounding for the winner. Just what a great upset should do. There is a very slim chance that we will ever see an upset like this again.  That is what makes this so special and also the best upset in MMA history.