UFC Vegas 121 Underdogs: Why Alatengheili Is Worth a Look at +300

Austin Swaim|published: Sat 26th September, 09:16 2026Apr 26, 2025; Kansas City, Missouri, UNITED STATES; Alatengheili (blue gloves) prepares to fight Da’Mon Blackshear (not pictured) during UFC Fight Night at T-Mobile Center. Mandatory Credit: William Purnell-Imagn Images Many feel the way that you have to bet on UFC is parlaying heavy favorites together, but underdogs win approximately 35% of the time in the world’s largest MMA promotion. Don’t be afraid to hunt for plus money.Years ago, I developed a predictive model that uses in-fight stats and fighter attributes to simulate UFC fight outcomes — so long as the combatants had at least 30 completed octagon minutes or 5 total fights. I found that, in the UFC, moneyline favorites are usually overvalued.How is that possible? Well, in a fight environment with as many variables per second as MMA, it’s hard to see the difference between -150 and -350 in real time. Great bets can lose. Terrible bets can win by lucky measures.Every week, I’m going to give you my favorite underdog bet of the week. They’ll usually be showing value in my model, and I’ll explain their path to victory.Here’s my favorite bit of plus money available for UFC Fight Night: Rosas Jr. vs. Barcelos.Note: All fight odds come via Polymarket, the official prediction market of UFC.Swaim’s Underdog of the Week: Alatengheili (+300)Model Odds: +145Model’s Favorite Exact Outcome and Implied Odds: Decision (+232) Our Current Best OffersChannel debug: betting With at least seven favorites of -200, it’s a lopsided weekend at the Apex, but — inevitably — one of these heavy favorites is going to lose. It makes total sense in the bantamweight prelim between John Castaneda and Alatengheili.Overall, the bout is trading at 75% likelihood of going the full distance on Polymarket. My model (59.3%) is slightly behind that, but it’s still the likeliest outcome. After all, six of Castaneda’s nine UFC fights have gone the distance, and Alatengheili has seen all 15 minutes in eight of nine bouts, and he won via first-round (T)KO in the lone exception.With that the case, would it be unprecedented for “The Mongolian Knight” to get the nod? He’s 4-3 in UFC decisions. Castaneda is 2-3. Both also have a draw.Speaking of draws, “Sexi Mexi” just went to one with Mark Vologdin, who has a -2.73 striking success rate (SSR). All of a sudden, Alatengheili’s -2.30 SSR — against better competition like Da’Mon Blackshear, Casey Kenney, and Chris Gutierrez — isn’t that scary.Castaneda’s career-long issues with weight management and endurance make him an unreliable favorite. It seems the issues aren’t resolved, either, as the American needed to shave his head to make this division’s weight limit: Alatengheili can really push a grappling pace to tax that gas tank. He attempts 4.07 takedowns per 15 minutes, landing a higher percentage of them (43%) than Castaneda (37%). Both fighters have an identical 75% takedown defense.Utilizing a five-inch reach advantage, I expect Castaneda to be ahead at distance, but I hardly have confidence that he shows the efficiency or power (0.62% knockdown rate) to pull away.I agree with my model here. While I’ve got Castaneda 30.0% likely to finish the fight compared to Alatengheili’s low chances (10.7%), a full fight could favor the Mongolian. I’ve got him at 30.1% likely to win a decision here, compared to 29.2% for Castaneda, and that sort of matches what you have to feel will be a Round 3 dynamic that significantly favors the underdog’s cardio should we get there. Our Current Best OffersChannel debug: betting