Sinosic is a UFC veteran holding a record of 1 win and 6 losses within the UFC, at the time the statistically worst record in promotional history, contributing to the 8 wins, 12 losses and 2 draws in his mixed martial arts career. He made his UFC debut defeating Jeremy Horn by armbar at UFC 30, considered a huge upset at the time, and was then offered a match with Tito Ortiz, who was then the UFC Light Heavyweight Champion at UFC 32. Sinosic was defeated by Ortiz in the first round via Technical knockout (TKO).