Everyone loves an underdog, a Cinderella story, a David and Goliath-like battle, and since the UFC’s proliferation, there has been no shortage of upsets. Upsets are what make tournaments like March Madness so loved, what makes the Oakland Athletics’ ability to reach the playoffs year in-and-out with little financial backing so special, and why fans stick around until the end of the fourth quarter. Upsets in the UFC are special and unique to the sport because they don’t feature a team, or differing payrolls, and fighters can either loose or gain weight to fight in different classes. Then there’s the very primal attraction that comes with seeing men dueling it out to claim supremacy over the other; an attraction that dates back to the medieval days of gladiators. Now, as the organization just recently celebrated its twentieth anniversary, it’s time to take a look at the 13 greatest upsets in the history of the Ultimate Fighting Championship.

13. UFC 162: Anderson Silva vs. Chris Weidman

It’s hard to believe now, looking back, but this was the beginning of the end for Anderson Silva. Before the fight, Silva was on a 17-fight win streak. He had defended the Middleweight title a record ten straight times. Not only had he not lost in over seven years, but he regularly made his wins look easy. He had begun taunting opponents mid-fight and dropping his hand, daring them to even try to punch him.

When he tried to pull the same stunt against Chris Weidman, he was promptly tagged on the chin and knocked out cold. At the time, it was a shocking upset. Silva later lost a rematch when he suffered a gruesome broken leg during the fight, and he hasn’t won again since (he did win a decision against Nick Diaz at UFC 183, but it was later turned into a no-decision after Silva tested positive for steroids).

12. UFC 196: Nate Diaz vs. Conor McGregor

At a time when it seemed like Conor McGregor could do no wrong, he took a huge misstep at UFC 196. Despite being the champion at 145 pounds, McGregor made a bold jump up in weight to challenge the Lightweight champion Rafael dos Anjos at 155 pounds. When that fight fell through due to dos Anjos breaking his foot in training, McGregor eventually agreed to a fight with the trash-talking Nate Diaz — at 170 pounds. That’s two weight classes above his normal division, for those keeping track.

Diaz had a long history of inconsistent performances and McGregor was coming off a 13-second KO of Jose Aldo, one of the greatest champions of all-time. The Vegas betting odds were stacked in the Irishman’s favor. But Diaz, never one to give a crap what anyone else thinks, silenced the pro-McGregor crowd by choking Conor out in the second round, after out-striking him for the entire first round.

(AP Photo/Eric Jamison)

11. UFC 76: Keith Jardine vs. Chuck Liddell

Liddell really needed to win this fight. After losing to Quentin “Rampage” Jackson for the second time, and losing his light heavyweight title, the ageing Liddell was out to prove that he still belonged fighting in the UFC. However, Jardine, a forgettable Ultimate Fighter contestant from Season Two, stood in his way of another title shot. “The Iceman” was in desperate need of ice after this bout. Jardine worked over his midsection and legs with a flurry of kicks and punches that left the former champion battered. At the end of the third round, UFC fans were in limbo, waiting for the judges to declare Jardine the winner. But, as judged sports often have it, the official scoring saw Jardine win by only a split decision. It didn’t matter to many UFC fans though, because the evidence was clear: Jardine put a beating down on Liddell and deserved the win.

THE CANADIAN PRESS/Neil Davidson

10. UFC 43: Chuck Liddell vs. Randy Couture I

This was the first of three fights in what later became the Liddell/Couture trilogy. Liddell was on a ten fight winning streak, while Couture, having lost his past two fights and stepping into the ring as a 39-year-old, was well past the apex of his legendary UFC career. “I thought I was the best,” said Liddell in a post-fight interview sometime after the bout. Boy was he wrong. Couture, showcasing his superior grappling techniques, mounted Liddell late in the third round and eventually landed enough punches to win by TKO at 2:39. Couture won the light heavyweight belt that night and with his two previous championship reigns in the heavyweight division, became the first UFC fighter to win two belts in two different weight classes.

THE CANADIAN PRESS/ Neil Davidson

9. UFC 112: Frankie Edgar vs. B.J. Penn I

Penn came into this fight having defended the lightweight title three straight times and had betting odds of -900 on him, which in betting terms is considered to be a huge favorite. Edgar, a hopeless nobody, and not even considered to be the hardest opponent Penn had faced at the lightweight level, was practically defaulted the title shot because there was no one left. Well on this night, Edgar earned his nickname “The Answer”, when he stood toe-to-toe with “The Prodigy” Penn. The two went all five rounds and Edgar won a controversial unanimous decision to strip Penn of the lightweight title. Shortly after was Edgar vs. Penn II, and Edgar silenced critics by winning the bout in even more convincing fashion, and so (arguably) began the demise of Penn.

(AP Photo/Gregory Payan)

8. UFC 132: Tito Ortiz vs. Ryan Bader

This fight requires some back story to put it all into context. Going into UFC 132, Ortiz, a once dominant force in the world of UFC, had not won a fight in five years. That’s right, his last victory was in 2006, and this bout was in 2011. Everyone wrote off Ortiz and most critics and fans hoped putting him against Bader would result in a beating that would all but force the much maligned fighter to retire. Ortiz, unphased by Bader’s 13-1 record, and quite obviously bitter that no one listened (or cared for that matter) that the washed up fighter’s back was in great shape heading into the fight, reminded the fighting world of his existence with a right hook that shook the rafters of the arena. Ortiz managed to put Bader in a guillotine and forced him to tap out.

(AP Photo/Eric Jamison)

7. UFC 68: Randy Couture vs. Tim Sylvia

If you learn anything by reading this list, it ought to be this: never count out the old guy. Couture came out of retirement to fight Sylvia, and when the two stood next to one another, the disparity in age and size were evident. Couture was 43, Sylvia was 30. Sylvia, at 6’8″, was six inches taller than Couture, outweighed him by over forty pounds, and had a reach that was a foot longer than Couture’s.  The fight began in the most unpredictable of fashions, with Couture getting underneath Sylvia to land a massive punch to the jaw of the giant, one that left Sylvia stunned. The bout went five rounds, the crowd never left its feet, and Couture never let his foot off the pedal, dominating the fight in all aspects on his way to a convincing win.

(CP PHOTO/Neil Davidson)

6. UFC 1: Royce Gracie Winning UFC 1

He was tall, he was lanky, he was trying to introduce this new style of fighting called Brazilian Jiu-Jitsu. He was Royce Gracie, the founding father of the UFC. The Gracie legacy in the UFC, and to mixed martial arts in general, cannot be understated, but his victory in the first official UFC comes with upsets and controversies; two characteristics that continue to follow the sport today. Gracie put down three fighters (including UFC Hall of Famer Ken Shamrock) to take home the title that night, and he did it all in just four minutes and fifty-nine seconds of fight time. The real controversy at UFC 1 came against the legend Shamrock in the semi-finals. Gracie got Shamrock in a rear choke and forced a submission, but Shamrock alleges that Gracie used his gi suit as a tool for ligature strangulation to aid him with the submission. The allegations fell on deaf ears and Gracie remains the first ever champion of the UFC.

5. UFC 46: B.J. Penn vs. Matt Hughes

B.J. Penn had the ability to become one of the most prolific fighters in UFC history, but it was his inconsistency in big fights that forever put a blemish on what was otherwise an incredibly successful career with the UFC. So after losing twice in shots at the lightweight title (one was technically a draw), Penn decided that it was time to shake things up. But not many expected that shake up to include a jump to the taller and heavier welterweight division. Penn got in the ring against the incumbent champion Matt Hughes, and for most critics, this fight was going to be a wash; a stark reminder that sometimes, the size of the dog in the fight does matter. But Penn was having none of it. Penn took Hughes down early and worked the ground game. After wearing him down for almost five straight minutes, Penn locked in a rear naked choke and submitted Hughes with only 21 seconds left in Round One.

(AP Photo/Duane Burleson)

4. UFC 76: Forrest Griffin vs. Mauricio Rua

If the UFC ever offered a fighter a sacrificial lamb as a sort of “thank-you” for joining their association, throwing one time Ultimate Fighter champion Forrest Griffin into the cage against Pride’s greatest uncrowned legend, Maurico “Shogun” Rua, was the time. Griffin was the first to get opened up when he was mounted by Rua and hit with a big right elbow above the eyebrow. With blood trickling down his face and into his eye, Griffin was relentless in his determination to prove he belonged in the UFC as a top fighter. By the second round, Rua’s hands were already dropping, and with just fifteen seconds left in the third round, Griffin executed a rear naked choke to perfection, forcing the Brazilian to tap, and sent shockwaves across the UFC.

(AP Photo/Felipe Dana)

3. UFC 70: Gabriel Gonzaga vs. Mirko Cro Cop

When a UFC fighter lands a punch to the head, everyone cheers. When a UFC fighter lands a kick to the head, everyone cringes. However, no one expected Mirko Cro Cop, a fighter famous for punishing kicks, to receive a taste of his own medicine when he went into the ring against Gonzaga. One of Pride’s most prized heavyweight fighter, Cro Cop was in a number one contenders bout with Gonzaga during an era where UFC’s heavyweight division was weak and uneventful. Cro Cop’s success in Pride made him a big time favorite coming into the event, but a first round head kick – one of the most iconic head kicks in the history of the UFC – knocked Cro Cop out cold and sent Gonzaga to the heavyweight title fight. Equally as disturbing as the blow to the head was the fashion in which Cro Cop’s ankle buckled underneath the enormity of his frame, as it was plummeting towards the ground.

(AP Photo/Felipe Dana)

2. UFC 69: Matt Serra vs. Georges St-Pierre I

The look on Serra’s face said it all. Coming into the fight, St-Pierre was a -1100 favorite, and the fight was thought to be just a formality on the road to GSP’s rising stardom in the welterweight division of the UFC. In what has gone down as the greatest upset in UFC history, Serra knocked out the legendary Canadian in the first round with an onslaught of punches. As Rogan approached Serra with the belt after the fight, Serra, one of the UFC’s most eccentric personalities, took the belt and said one of the most iconic lines in UFC post-fight history, “Joe, I’m really, really hungry. I was wondering if you and Dana had some humble pie in the back?”

(CP PICTURE ARCHIVE/Neil Davidson)

1. UFC 193: Holly Holm vs. Ronda Rousey

Ronda Rousey was the fighter who finally changed Dana White’s mind about allowing women to compete in the UFC. Although other MMA promotions already had women’s divisions, the UFC held out much longer, citing that there wasn’t anyone marketable enough — plus a lack of depth — to form a successful female weight class. Rousey burst on the scene, proving everyone wrong. She tore through opponents with ease, often in less than a minute. Holly Holm was expected to be just another name on Rousey’s long list of victims, coming into the fight for the woman’s bantamweight title as a huge underdog.

Instead she out-classed Rousey with incredible boxing, en route to a second round finish via a spectacular head kick. MMA news outlet Sherdog called the fight “2015’s Biggest Upset,” but it was also one of the biggest upsets in company history.

(AP Photo/Andy Brownbill)