Sherdog’s 2025 Upset of the Year

When you get down to it, upsets are a big part of the reason we watch sports, or perhaps it would be more accurate to say that the possibility of the upset is a big part of the reason. If the favorite went out and won every time, or even 99% of the time, much of the intrigue, suspense and emotion that keeps fans on the edge of their seats would be lost, to say nothing of what it would do to the multi-billion-dollar gambling industry that hovers over just about every form of athletic competition in the world.

Mixed martial arts does not need to worry about falling into that kind of rut anytime soon. As an individual sport with diverse paths to victory, a minimal but constantly evolving ruleset and often inconsistent judging and officiating, MMA is one of the most upset-prone major sports. Major sports books, whose lines are driven by incoming bets, get the winner on the right side of the moneyline only about two-thirds of the time, and even elite prognosticators struggle to pick winners straight up at a 75% clip over an extended period.

MMA’s Biggest Upsets of 2025

So, in a sport in which the underdog wins a third of the time, how does one determine the “Upset of the Year?” Certainly, raw numbers play a part; every year we see a few 10-to-1 favorites stumble—or even 20-to-1, as Biaggio Ali Walsh did at PFL 7 in June, entering the cage at a prohibitive -2000 against Ronnie Gibbs only to be choked to sleep. Similarly, at UFC 311 in January, Raoni Barcelos turned back the clock, and at least slowed the Payton Talbott hype train, handing the previously undefeated prospect his first career loss despite the -1100 betting line in Talbott’s favor. Those two fights, the biggest betting upsets of the year in global promotions, earned votes from the Sherdog staff, as did Costello van Steenis’ dramatic rally to choke out Johnny Eblen at PFL Cape Town on July 19, the biggest upset of 2025 in a major title fight and our winner for “Submission of the Year.”

Still, upsets are defined by that elusive, magical element of surprise. Even more than sheer numerical fireworks, they are about the feeling of our expectations being upended, and when it came to MMA defying our expectations in high-profile moments, one performance stood above all the rest in the eyes of the voting panel.

The Rarest Kind of Upset in MMA

Big upsets tend to fall into a few basic categories. There are “lightning in a bottle” moments, like Matt Serra’s defeat of Georges St. Pierre at UFC 69, where a massive favorite fell to a performance that, if not a fluke, was at least unlikely to be repeated even if the two fought 10 more times. Conversely, there are “now we know” upsets, such as Holly Holm’s destruction of Ronda Rousey at UFC 193, in which an underdog exposed the flaws in a previously invincible champion, showed the betting lines to have been mistaken, and left the impression that if the two fought again, it would probably play out much the same.

In contrast to those two categories, there is a third, the rarest of all: a rematch between two fighters who had fought relatively recently, whose first meeting had been decisive in one fighter’s favor, and who had given no particular reason to believe the second go-round would be different. That is the perfect descriptor for the Petr Yan-Merab Dvalishvili bantamweight title fight that served as the main event of UFC 323 on Dec. 6.

Dvalishvili and Yan met for the first time at UFC Fight Night 221 in March of 2023. At the time, Dvalishvili was on an eight-fight winning streak and arguably the most overdue title challenger in the promotion, while Yan was a recent former champ looking to snap the first losing skid of his career.

Despite their contrasting momentum, Yan entered the Octagon as a greater than 2-to-1 favorite, which only set the table for Dvalishvili’s coming-out party. The relentless Georgian delivered a spectacular showing, running Yan into the ground with his trademark frenetic pace, landing 11 of his mind-boggling 49 attempted takedowns. If that ratio does not sound very impressive, consider that Yan had been taken down only seven times in his first 11 UFC outings combined. It was a statement victory, summed up perfectly by the two men’s demeanor after the final horn, before the result was even read: Dvalishvili running around, jubilant and apparently ready to go another five rounds; Yan looking exhausted, frustrated and dejected.

Both Yan and Dvalishvili experienced success in the two and a half years following their first meeting. Dvalishvili won, won and won some more until the UFC could no longer ignore him, capturing the bantamweight title and then defending it three times in 2025, establishing himself as one of the top pound-for-pound fighters in the sport. Yan righted the ship, winning three straight against solid Top 15 opposition. Still, when the two were booked for a rematch, it felt like a comment on the state of the division and Dvalishvili’s endless win streak more than an endorsement of Yan’s chances. Unsurprisingly, the odds had flipped and then some: Dvalishvili was a greater than 4-to-1 favorite on the books on the night of the fight.

Once they stepped into the cage, the dynamic was immediately different from that of their first fight. Yan, who has always been known as a slow starter, pushed the pace right away, putting the hyper-aggressive champion on his back foot. Perhaps even more surprising, Yan not only shrugged off Dvalishvili’s early takedown attempts, but started shooting beautifully timed takedowns of his own, grounding “The Machine” in a way we had never before seen.

Whether due to surprise at Yan’s game plan or some other reason, Dvalishvili struggled mightily. The champ’s brutally effective leg kicks and constant barrage of takedowns, the key elements of his victory in their first meeting, all but disappeared.

Without those weapons to blunt Yan’s boxing, Dvalishvili was effectively stuck on the feet, where his frantic but usually effective striking was exposed badly by Yan’s crisp, clean combination punching. While Dvalishvili has always been hittable and usually sports some damage on his grinning mug even in victory, by the time Yan was done with him he looked as though he had been in a car wreck. Unbuckled.

With the pattern set by the end of Round 1, what is most surprising is how little it changed over the rest of the fight. The judges’ final scores of 48-47, 49-46 and 49-46 may not even do justice to how decisive it was. All three official scorers awarded the first round to the champ; one of the time-honored tropes of big upsets, after all, is that it often takes the judges a while to realize that the favored fighter is losing.

The media scores, of which greater than two-thirds came in 50-45 in Yan’s favor, tell the story more accurately. It isn’t that Dvalishvili ever faded or wilted—he was competitive in every round—but that Yan was firmly in the driver’s seat the entire time. The two fighters’ body language after the final horn was practically a mirror image of the first meeting.

After the decision was read and Yan was confirmed a two-time UFC bantamweight champion, the MMA world sat down to digest the final pay-per-view headliner of the year; maybe the last one ever. Was Dvalishvili compromised by his relentless schedule—he had been attempting to make history by being the first UFC champ to defend four times in a calendar year—or had Yan and his team simply solved the riddle? Of all the possible takeaways from the fight, perhaps the most surprising is that a trilogy now seems not only necessary but appealing. Whether we get Yan-Dvalishvili 3 in the coming year only time will tell, but what’s certain for now is that their second meeting is Sherdog’s “Upset of the Year” for 2025.