At the beginning of 2013, Serrano retired from wrestling to focus on his MMA career.[2] He had two unsanctioned MMA fights in 2013, both of which he won.[2]
In March 2014, Serrano was announced as having signed an 8-fight contract with Resurrection Fighting Alliance.[3] However, he never debuted before joining the cast of The Ultimate Fighter.
The Ultimate Fighter
In May 2014, Serrano was announced as a member of the cast of fighters participating The Ultimate Fighter: Latin America.[4] He competed as a bantamweight for Team Werdum. In his first fight on the show, Serrano lost to Alejandro Pérez by unanimous decision.
Serrano faced former TUF: Latin America castmate Bentley Syler on March 21, 2015 at UFC Fight Night 62.[5] Serrano won the fight by knockout in the third round.[6] The win earned him a Performance of the Night bonus .[7]
Serrano faced Yao Zhikui on November 28, 2015 at UFC Fight Night 79.[8] He won the fight via TKO in the first round after Yao severely injured his arm while trying to defend a takedown.[9]
Serrano was originally expected to face Ray Borg on July 30, 2016 at UFC 201.[10] However Borg pulled out of the fight and was replaced by Ryan Benoit.[11] He lost the fight via split decision.[12]
Serrano faced Hector Sandoval on December 17, 2016 at UFC on Fox 22.[13] He lost the fight via unanimous decision and was subsequently released from the promotion.[14]