UFC Vegas 121 preview: ‘Rosas Jr. vs Barcelos’ main, co-main event predictions

Ultimate Fighting Championship (UFC) is just one day away from the upcoming UFC Vegas 121 mixed martial arts (MMA) event, which is set to go down tomorrow night (Sat., Sept. 26, 2026) on Paramount+ from inside Meta Apex in Las Vegas, Nevada. UFC Vegas 121 features a bantamweight main event between 135-pound standouts Raul Rosas Jr. and Raoni Barcelos, a five-round showdown that could shake up the division Top 10.

Before we dive into the main and co-main event, which includes the 185-pound collision between unranked middleweight bruisers Rodolfo Vieira and Robert Bryczek, check out Andrew Richardson’s “X-Factor” breakdown for the rest of the UFC Vegas 121 main card by clicking here. Get all the latest “Rosas Jr. vs. Barcelos” odds and betting props courtesy of FanDuel right here. For complete UFC Vegas 121 live results and play-by-play click here.

135 lbs.: Raul Rosas Jr. vs. Raoni Barcelos

Raul “El Niño Problema” Rosas Jr.
Record: 12-1 | Age: 21 | Betting line: -165
Wins: 2 KO/TKO, 6 SUB, 4 DEC | Losses: 0 KO/TKO, 0 SUB, 1 DEC
Height: 5’9” | Reach: 67” | Stance: Switch
Significant Strikes Landed Per Minute: 1.34 | Striking accuracy: 42%
Strikes Absorbed Per Minute: 1.24 | Striking Defense: 52%
Takedown Average: 6.10 (54% accuracy) | Takedown Defense: 25%
Current Ranking: No. 12 | Last fight: Unanimous decision win over Rob Font

Raoni Barcelos
Record: 22-5 | Age: 39 | Betting line: +135
Wins: 8 KO/TKO, 3 SUB, 11 DEC | Losses: 1 KO/TKO, 1 SUB, 3 DEC
Height: 5’7“ | Reach: 67” | Stance: Orthodox
Significant Strikes Landed Per Minute: 4.65 | Striking accuracy: 51%
Strikes Absorbed Per Minute: 4.24 | Striking Defense: 60%
Takedown Average: 2.51 (31% accuracy) | Takedown Defense: 87%
Current Ranking: No. 13 | Last fight: Split decision win over Montel Jackson

Raul Rosas Jr. is just 21 years old but already 12-1 in MMA and 6-1 under the UFC banner. “El Niño Problema” is not ranked in the official Meta Rankings but the media has him ranked one spot above Raoni Barcelos at No. 12, for whatever that’s worth (hint: not much). Rosas Jr. is fairly-one dimensional fighter, relying on his wrestling to neutralize his opponents while hunting for the submission, leading to six taps in 12 wins. After watching Gable Steveson get knocked into the shadow realm last weekend in Los Angeles, I don’t expect Rosas Jr. to start experimenting with his standup — and why should he? He’s comfortably outwrestled seven of his eight opponents and needs just three takedowns in this fight to move into No. 3 all-time in the bantamweight record book. That said, he’s up against a fellow wrestler ranked No. 8 all-time in takedowns who will be looking for a couple of takedowns of his own.

“I’ve got to be ready for short notice fights, be willing to take risks, and this Saturday, make a big statement for sure,” Rosas Jr. told Full Send MMA. “Not just a win, but I’ve got to make a statement. If by 25 I accomplish everything that I want to accomplish in my career, I’m just going to step back from the sport. The goal is to get the belt and then defend it a couple of times, try to challenge myself, go up a weight class, maybe two, and after I’m done, like, I run out of goals, that’s when I’m just gonna quit. It could be 26, 27, 28, but I’m just saying whenever I’m done with my goals, that’s when I’m gonna step out of the game.”

Raoni Barcelos went from promising prospect, to middling bantamweight, to red-hot veteran over the last eight years. He’s currently the winner of five straight, upsetting bantamweight wunderkind Payton Talbott and turning away former champion Cody Garbrandt, among others. Like Rosas Jr., Barcelos relies heavily on offensive wresting and averages 2.5 takedowns per fight (compared to 6.1 for his opponent). There’s no question Barcelos has faced tougher competition throughout his career, going head-to-head against the likes of Umar and Said Nurmagomedov, as well as grizzled veterans like Ricky Simon and Chris Gutierrez. If there’s a critique to be made, it’s that Barcelos has only finished one fight over the last seven years, not a great sign for a fighter who is pushing 40 years old and still ranked outside the Top 10.

“It doesn’t scare me,” Barcelos said about his opponent’s youth during the UFC Vegas 121 media day. “I think after the Payton Talbott fight, I just became more and more confident in myself, seeing what I could do. Raul is tough and he’s going to keep growing. There are a lot of other great fighters for him to fight. There are a lot of other great fights for him but this is my moment. I really believe this is my moment and my time. I think building a story is what brings you fans. I really have a story, and I think people are noticing that. I think I’ve been gaining more fans, and I’m going to gain even more fans. It’s really cool to see that and just keep going with what I’m doing.”

Barcelos is the more experience, well-rounded fighter and I would pick him in a three-round fight. But neither combatant has gone five rounds under the UFC banner and I can’t pick a 39-year-old veteran over a 21-year-old dynamo, especially when both fighters are going to be wrestling for the majority of the fight.

Prediction: Rosas Jr. def. Barcelos by unanimous decision

185 lbs.: Rodolfo Vieira vs. Robert Bryczek

Rodolfo “The Black Belt Hunter” Vieira
Record: 11-5 | Age: 36 | Betting line: -165
Wins: 1 KO/TKO, 9 SUB, 1 DEC | Losses: 1 KO/TKO, 1 SUB, 3 DEC
Height: 6’0“ | Reach: 73” | Stance: Orthodox
Significant Strikes Landed Per Minute: 3.43 | Striking accuracy: 54%
Strikes Absorbed Per Minute: 4.28 | Striking Defense: 49%
Takedown Average: 2.87 (22% accuracy) | Takedown Defense: 60%
Current Ranking: Unranked | Last fight: Unanimous decision loss to Eric McConico

Robert Bryczek
Record: 18-7 | Age: 36 | Betting line: +135
Wins: 12 KO/TKO, 1 SUB, 5 DEC | Losses: 1 KO/TKO, 1 SUB, 5 DEC
Height: 6’0“ | Reach: 75” | Stance: Orthodox
Significant Strikes Landed Per Minute: 2.80 | Striking accuracy: 37%
Strikes Absorbed Per Minute: 4.51 | Striking Defense: 55%
Takedown Average: 0.36 (100% accuracy) | Takedown Defense: 71%
Current Ranking: Unranked | Last fight: Unanimous decision loss to Cameron Rowston

Earlier I mentioned the old guard at 155 pounds and well, you don’t get much older than Diego Ferreira, who’s halfway

Prediction: xxx

Don’t forget to check out the rest of the UFC Vegas 121 main card predictions RIGHT HERE.