UFC Best Bets, Predictions & Expert Picks Saturday, September 19, 2026 — UFC 331

Analyse

The market is treating Robelis Despaigne like a near certainty at minus 550, but the model sees this completely differently. Despaigne is projected to win only 35.6% of the time, while Tai Tuivasa owns a 64.4% win probability. That creates a massive value gap on Tuivasa at plus 413, and the recommendation is clear: bet the underdog moneyline. Tuivasa brings the experience and the ranking edge into this heavyweight matchup. He's 15 and 10 and sits at number 15 in the rankings, while Despaigne is unranked with a 6 and 2 record. The key factor is Tuivasa's striking advantage, which matters enormously in a three round heavyweight fight where one clean exchange can decide everything. Despaigne does hold a nine inch reach advantage, giving him a clear range weapon, but reach alone doesn't erase the model's read on the striking matchup. This fight is expected to last only 1.8 rounds, with just a 16% chance of reaching the scorecards. That's important. We aren't asking Tuivasa to win a long technical battle. The model expects a fast finish, and Tuivasa's best path is to pressure the longer fighter before Despaigne can consistently use that reach. At this price, the upside is enormous. The favorite needs to be right almost every time. Tuivasa only needs one clean heavyweight connection.

Public fade

Casual bettors see the unranked fighter, the 6 and 2 record, and the nine inch reach disadvantage, then automatically grab Despaigne at any price. But the model gives Tuivasa the striking edge and a 64.4% win probability. That makes the favorite one of the biggest traps on the UFC 331 card.

Analyse

Gable Steveson is priced like an unbeatable heavyweight at minus 2400, but that number is doing all the talking here. The model gives Steveson a 62.8% win probability, which is strong, yet nowhere near the level needed to justify such a massive price. Sean Sharaf is projected to win 37.2% of the time, creating a 28.9% moneyline edge at plus 1100. Sharaf enters with a 4 and 2 record, while Steveson is undefeated at 4 and 0. That perfect record is clearly driving public confidence, but four professional wins don't justify laying this kind of number when the model still sees a meaningful chance for the underdog. Sharaf also owns a three inch reach advantage, measuring 77 inches compared with Steveson's 74 inches. The key factor is Steveson's striking advantage, so Sharaf needs to avoid getting drawn into a clean exchange and use his length to make the favorite work. This is projected as another short heavyweight fight, with an expected duration of 1.8 rounds and only a 17% chance of going the distance. The model gives KO or TKO a 74% confidence rating. That creates volatility, and volatility is exactly what you want when holding a huge underdog ticket. Steveson may be the more likely winner, but likely isn't the same as profitable. At plus 1100, Sharaf doesn't need to win often to make this bet worthwhile. One clean shot can flip the entire fight.

Public fade

The public is buying Steveson's undefeated record and treating this as a foregone conclusion. But his four and zero mark has come in a very small sample, and the model still gives Sharaf a 37.2% chance to win. At minus 2400, the favorite carries almost all the risk while offering very little reward.

Analyse

Ryan Gandra is the favorite at minus 520, but Ozzy Diaz is the side with the value. The model projects Diaz to win 41.4% of the time compared with 58.6% for Gandra, creating a 21.4% edge on the underdog moneyline at plus 400. That is a significant gap between the market price and the actual matchup outlook. The records explain why the public will gravitate toward Gandra. He's 10 and 1, while Diaz is 10 and 4. Still, the most important matchup factor points toward Diaz: his striking advantage. Diaz also owns a five inch reach advantage, with a 79 inch reach compared with Gandra's 74 inches. In a three round middleweight bout, that length can help Diaz control distance, land first, and force Gandra to take risks getting inside. The model isn't treating the reach as a minor detail. It's part of the reason this fight is much closer than the odds suggest. The projected fight duration is 2.1 rounds, and the model gives it a 30% chance of reaching the scorecards. KO or TKO carries a 47% confidence rating, so a finish is the most likely method, though this fight has a better chance of seeing the judges than the other two recommended bouts. That matters because Diaz can win through sustained striking or a single damaging sequence. Gandra is more likely to win, but not by enough to justify minus 520. Diaz at plus 400 is the sharper position.

Public fade

Bettors are focusing on Gandra's 10 and 1 record and assuming Diaz's four losses make him unreliable. But the model gives Diaz a 41.4% win probability and identifies his striking and five inch reach advantage as the key matchup factors. That is far too much underdog equity to ignore at plus 400.