If Megan Anderson manages to unseat Amanda Nunes at UFC 259, it’ll go down as one of the greatest upsets of all time in a UFC title fight.
But will it be the biggest upset? It’s definitely a possibility when you consider that Nunes is almost certainly the greatest female fighter in UFC history.
However, the UFC has seen plenty of other major upsets in title fights over the years, many of which left UFC fans utterly stunned.
Here are the five greatest upsets of all time in UFC title fights.
#1 BJ Penn vs. Matt Hughes – UFC 46
Back in 2004, it was pretty fair to state that Matt Hughes was not just the most dominant Welterweight in the UFC – he was probably the greatest Welterweight in the history of MMA.
Hughes won the UFC Welterweight title in 2001 strange circumstances – one of the UFC’s only double knockout finishes against Carlos Newton. But in the years that followed, he’d ran roughshod over the division.
By January 2004, the wrestler had successfully defended his UFC title five times, beating Hayato Sakurai, Newton in a rematch, Gil Castillo, Sean Sherk, and Frank Trigg.
Essentially, he’d cleaned out the weight class.
That’s why eyebrows were raised when the UFC decided to hand the next title shot to BJ Penn, who at the time had never competed higher than 155lbs.
To make matters even stranger, The Prodigy wasn’t even coming off a win. Instead, his last fight had been a draw with Caol Uno that prevented him from claiming the UFC Lightweight title.
Penn came into UFC 46 about as big an underdog as you could possibly get. But evidently, nobody told the Hawaiian.
He landed a big punch that hurt Hughes in the early going, causing the champ to botch a takedown attempt and wind up on his back.
And from there, Penn passed to full mount, took Hughes’ back, and choked him out to win the title.
Penn would never defend his UFC Welterweight crown, instead vacating it to leave the promotion. Despite this, his win over the seemingly-unstoppable Hughes still stands as an all-time great upset.
#2 Matt Serra vs. Georges St. Pierre – UFC 69
2007 would be remembered as the ‘Year of the Upset’ in the UFC, but no upsets were bigger than this one at UFC 69.
To many fans, Matt Serra wasn’t even a deserving contender for the UFC Welterweight title. He’d earned his shot not by beating top-ranked fighters but by coming out on top of the poorly received TUF 4 Welterweight bracket.
Reigning champion Georges St. Pierre, on the other hand, seemed unstoppable. He’d reeled off five straight wins over top contenders like Frank Trigg and BJ Penn and had destroyed dominant champ Matt Hughes to claim the title when they met at UFC 65.
But incredibly, the fight didn’t go St. Pierre’s way at all.
Caught behind the ear by a winging right hand early in the first round, GSP lost his equilibrium entirely. And Serra followed the shot up with more thudding punches until the Canadian could take no more.
When he was presented with his UFC title, even The Terror looked stunned by what he’d achieved. Essentially, he’d become the most unlikely UFC champion of all time.
Sure, he never managed to defend his title – losing it a year later to St. Pierre in a rematch. But the fact that this fight is still spoken about over a decade on tells you how big of an upset it was.
#3 Frankie Edgar vs. BJ Penn – UFC 112
April 2010’s UFC 112 was subtitled ‘Invincible,’ and it seemed like a fitting moniker for the show. Headlining the card were two title fights that featured two of the UFC’s most dominant champions – Anderson Silva and BJ Penn.
To say nobody expected either of the duo to lose would be an understatement.
But while Silva comfortably defended his UFC Middleweight crown against Demian Maia, Penn wasn’t so lucky.
Instead, he found himself on the losing end of a tight, arguably contentious decision against Frankie Edgar, losing his UFC Lightweight crown in the process.
The fight was remarkably close to call, with Penn seemingly taking the early rounds. Meanwhile, Edgar came on strong towards the latter part of the largely striking-based fight.
In the end, it was down to whether the judges valued Penn’s heavier blows or Edgar’s superior volume. And on this night, it would be volume that came out on top.
The upset was so huge that the UFC awarded Penn an immediate rematch four months later. However, this time, he was thoroughly outclassed by Edgar, who left no doubt as to who the better fighter was.
Penn was arguably never the same again.
#4 Chris Weidman vs. Anderson Silva – UFC 162
By July 2013, Anderson Silva had marked himself out as perhaps the most dominant champion in UFC history.
He’d claimed the UFC Middleweight title from Rich Franklin in October 2006 and had somehow defended it successfully on 10 occasions. Adding in non-title bouts, his unbeaten streak ran to 16 UFC fights.
UFC 162 saw him faced with a different kind of challenger, though – wrestler Chris Weidman. The All-American was unbeaten with five UFC wins, and his submission-heavy grappling style was expected to test Silva.
But nobody could’ve expected what actually happened.
Weidman proved to be a trickier opponent for Silva than The Spider expected. And when Silva decided to attempt a rope-a-dope strategy in the second round, leaning away from Weidman’s punches, he evidently underestimated the challenger’s long reach.
Weidman caught him cleanly with a huge left hook, knocking him down, and a couple of follow-up shots had Silva unconscious.
It was the first time that Silva had lost in the UFC, the first time he’d lost since 2005, and the first time he’d ever been stopped via strikes.
Undoubtedly, it was one of the UFC’s all-time great upsets.
And to prove that the first result was no fluke, Weidman repeated the feat in a rematch at UFC 168 – this time leaving Silva with a broken leg following a botched leg kick.
#5 Holly Holm vs. Ronda Rousey – UFC 193
Perhaps no other UFC fighter gave off the same air of dominance as Ronda Rousey.
The Olympic judoka came into the UFC in 2013 as the inaugural Women’s Bantamweight champion and had looked absolutely unstoppable inside the octagon.
By late 2015, she’d reeled off six straight UFC title defenses and had quickly established herself as one of the sport’s biggest superstars.
And incredibly, Rowdy Ronda appeared to be getting even better. Her three defenses against Alexis Davis, Cat Zingano, and Bethe Correia were won in just over a minute combined.
So when the UFC booked her to headline their first show in Melbourne, Australia, against former professional boxer Holly Holm, it felt like it’d be business as usual.
Sure, Holm was the best striker Rousey had ever faced. But she’d also never stopped an opponent in the UFC and hadn’t really impressed in her first two fights.
However, UFC fans around the world were left in stunned silence when Holm didn’t just beat Rousey but absolutely destroyed her with a second-round knockout.
The fight was the equivalent of a bull against a supremely skilled matador. Rousey continually charged towards Holm, looking to either land punches or grab a clinch.
But The Preacher’s Daughter looked ready for it and simply dodged her and landed nasty counter strikes.
When she dropped Rousey with a brutal head kick a minute into the second round, not only was the champion’s reign over, but her aura of dominance was absolutely shattered as well.
Rousey would only fight once more in the UFC and retired from MMA in 2017.