“El Niño Problema” is officially a main eventer.
Twenty-one-year-old Ultimate Fighting Championship (UFC) Bantamweight prospect Raul Rosas Jr. will headline his first UFC card against Brazilian veteran Raoni Barcelos at UFC Vegas 121 on Sat., Sept. 26, 2026, inside Meta Apex in Las Vegas, Nevada.
The promotion announced the five-round matchup this past weekend.
A lot to prove 💪@RaulRosasJr8 and @BarcelosRaoni clash in the #UFCVegas121 main event!
— UFC (@ufc) August 16, 2026
[ LIVE SEP 26 on @ParamountPlus ] pic.twitter.com/eIBnuDGxci
Rosas Jr. (12-1) is riding a five-fight winning streak heading into his first UFC main event. While he started his Octagon career on fire, finishing his first three victories, his last three wins have all come via unanimous decision against Aoriqileng, Vince Morales and, most recently, Rob Font.
Rosas Jr. became the youngest fighter in history to sign a UFC contract at 17 after earning his deal on Dana White’s Contender Series. He then became the youngest fighter to win inside the Octagon when he submitted Jay Perrin at 18 years and two months old (watch highlights).
The now-21-year-old still wants to become the youngest champion in UFC history—and he has time to do it. However, he must first get through an incredibly tough and experienced veteran.
It took Barcelos (22-5) 15 UFC appearances to finally secure his first main event opportunity, but his incredible late-career resurgence made the booking impossible to ignore.
Just three years ago, the Brazilian had lost four of five fights, including a brutal knockout loss to Umar Nurmagomedov. Since then, the veteran has completely turned his career around.
Barcelos is now riding a five-fight winning streak with victories over Cristian Quiñonez, Payton Talbott, former Bantamweight champion Cody Garbrandt, Ricky Simon and, most recently, Montel Jackson.
Here is what UFC Vegas 121 currently looks like:
Raul Rosas Jr. vs. Raoni Barcelos
Norma Dumont vs. Ailin Perez
Montel Jackson vs. Ricky Simon
Rodolfo Bellato vs. Christian Edwards
Yazmin Jauregui vs. Vanessa Demopoulos
John Castaneda vs. Alatengheili
Elves Brener vs. Josiah Harrell
Mickey Gall vs. Sedriques Dumas
TUF 34 Bantamweight Finale
TUF 34 Women’s Strawweight Finale
To checkout UFC’s upcoming schedule of events click here.