Regina Tarin will make her long-awaited UFC debut this Saturday after stepping in on short notice to replace Sofia Montenegro at UFC Mexico City on February 28.
According to MMA reporter Marcel Dorff, Montenegro has withdrawn from her scheduled women's flyweight prelim bout against Ernesta Kareckaite for undisclosed reasons. Tarin, an undefeated 21-year-old Mexican prospect, has answered the call as her replacement.
Tarin Brings 7-0 Record and Major Hype to UFC Debut
Nicknamed "Kill Bill," Tarin has compiled a perfect 7-0 professional record with finishes in six of seven bouts — four by knockout and two by submission. The lone decision came against Andrea Garcia in 2024.
The Mexico City native won the Budo Sento Championship women's bantamweight title with a fourth-round TKO of Luisa Cifuentes and also competed on Combate Global, where she stopped Kaytlin Neil — a veteran of Season 30 of The Ultimate Fighter. Three of her first four professional bouts ended in the opening round.
Due to the short-notice nature of the booking, the bout will be contested at a catchweight of 130 pounds rather than the standard 125-pound flyweight limit.
Kareckaite Returns From 13-Month Layoff
Kareckaite, a Lithuanian fighter who earned her UFC contract by beating Carli Judice via split decision on Dana White's Contender Series in 2023, holds a 1-1 record in the Octagon. She dropped a unanimous decision to Dione Barbosa at UFC 301 before bouncing back with a split decision win over Nicolle Caliari in January 2025.
"Heavy-Handed" returns from more than a year away from competition when she welcomes Tarin to the UFC this weekend.
UFC Mexico City Card Reshaped by Late Changes
The Tarin-Kareckaite replacement is the second significant shake-up to hit the UFC Mexico City card this fight week. Brandon Moreno is also facing a replacement opponent in the main event after original foe Asu Almabayev withdrew due to a hand injury, with Lone'er Kavanagh stepping in.
Tarin's debut carries extra narrative weight — she was originally booked for a DWCS appearance in 2025 before pulling out, with Montenegro filling her slot. Now the roles have reversed, and the undefeated prospect gets an even bigger stage for her promotional introduction on home soil. She is one of six DWCS Season 9 contract winners making their UFC debuts on the card this Saturday.
UFC Fight Night: Moreno vs. Kavanagh takes place at Arena CDMX on Saturday, February 28, streaming live on Paramount+ in the United States.