UFC 269 saw, without doubt, one of the greatest shocks in the sport's history, as the seemingly invincible Amanda Nunes was dethroned by Julianna Pena.
The Lioness established herself as the greatest female fighter of all time with wins over Ronda Rousey, Miesha Tate, Holly Holm, Cris Cyborg, Valentina Shevchenko and countless others, capturing two belts and leaving us all wondering where the run could possibly end.
Well, this weekend, we got our answer, and we're looking back at some of the biggest shocks in UFC history.
Rousey v Holm
Before Nunes, there was Rousey, who seemed just as (if not more) invincible. She'd won all 12 professional fights and had apparently run out of legitimate opponents. Her wins couldn't have been more comprehensive.
14 seconds, 16 seconds and 25 seconds (twice) were her fastest victories. Of her 12 wins, only one had got past the first round, so naturally, she was an enormous favourite against boxer Holly Holm, who was 9-0 in MMA at the time.
Rousey unusually opted not to touch gloves when prompted before the fight and, more unusually, tried to outstrike the striker.
She lost the first round and became desperate in the second, falling foul of the left hand, then the left foot, and the legend was defeated.
McGregor v Diaz
Rewind to early 2016, and Conor McGregor was on top of the world. He'd won the interim featherweight title against Chad Mendes, unifying the title after 13 seconds (or was it 12?) against Jose Aldo.
He'd then set his sights on being the first fighter in the UFC to hold two titles simultaneously.
But when Rafael dos Anjos pulled out of their scheduled fight with a foot injury, Nate Diaz stepped up.
Despite being just 11 days out from the fight, a deal was reached for McGregor to step up another weight class and take on Diaz at welterweight.
Such was the aura around Notorious at this time, it felt nothing could stop him.
But Diaz did.
McGregor started comfortably enough, landing some good lefts, opening Diaz up, but around seven minutes into the contest, his looked to be running on empty and the American began to take over.
Two minutes later, McGregor tapped.
Penn v Edgar
2010 saw BJ Penn put his lightweight title on the line against Frankie Edgar. Penn's only UFC defeats had come at welterweight against the legendary Georges St-Pierre and Matt Hughes and he was a big favourite to retain his title as the greatest lightweight the sport had known.
Edgar wasn't expected to trouble Penn, but he turned the tables, capturing the belt by unanimous decision.
St-Pierre v Serra
In 2007, Georges St-Pierre put his newly-acquired welterweight title on the line. Having avenged his defeat to future Hall of Famer Matt Hughes – who he admitted he'd lost to before even entering the Octagon, such was his admiration for him – GSP faced Matt Serra.
Serra was a massive underdog, but a clubbing right followed by a left put GSP in trouble, which he was unable to recover from.
Serra put Rush down again, applied the ground and pound, and took the belt, in arguably the greatest upset in UFC history.
Silva v Weidman
When discussing MMA's greatest of all time, you'll typically see Anderson Silva alongside GSP.
A fighter so elusive, so invincible, as with the likes of Nunes and Rousey, you wondered who could beat him.
The answer seemed to be no one; after stepping up to light heavyweight to fight Stephan Bonnar, the Spider decided to hang up the gloves, before returning back to middleweight to defend his title against Chris Weidman.
Weidman had amassed a 9-0 record in MMA and with Silva showboating in a not-unfamiliar fashion, standing with his hands on his hips, beckoning his opponent forward, the All-American caught him with a left which ended the longest title reign in UFC history.
Barao v Dillashaw
After losing his first professional MMA bout, Renan Barao went on an incredible undefeated run.
The Brazilian went 33 consecutive fights without defeat, almost unheard of in MMA, capturing the UFC bantamweight title and establishing himself as one of the sport's pound-for-pound best.
Step forward, TJ Dillashaw. Not only was the win itself so shocking, but the manner too, as he dominated the fight.
Barao simply couldn't live with his opponent, eventually being knocked out in the fifth round after a huge head kick, with Joe Rogan calling it the greatest performance he'd ever seen.