BJJ black belt and six-time Mundials Champion Márcio Cruz at UFC 57: Liddell vs. Couture 3 on February 4, 2006. In a shocking upset, Mir was defeated by first-round TKO. He returned to the octagon on July 8, 2006, at UFC 61: Bitter Rivals against Dan Christison. Mir won by unanimous decision when all three judges scored the bout 29–28. Mir was widely criticized following the bout due to his sloppy appearance and inability to finish a seemingly mismatched opponent. Despite the criticism, Mir was subsequently matched with Brandon Vera at UFC 65: Bad Intentions to determine the number one contender. Mir showed improved striking ability but was quickly stunned by a straight right from Vera, who then dropped him with knees from the Muay Thai clinch. Vera then secured side control and delivered a number of punches and elbows, forcing the referee to stop the fight at 1:09 of the first round. While preparing for UFC 140, Mir attributed his poor performance in his initial return bouts to lingering health issues following the accident. Rise back to title contention Mir was scheduled to fight kickboxer Antoni Hardonk at UFC Fight Night 9 on April 5, 2007, but had to drop out due to a shoulder injury. He faced Hardonk at UFC 74 and won via kimura at 1:17 of the first round. At the end of the bout, Mir walked to the cameras pointing at himself saying "I'm back!". Frank's wife Jennifer was shown on the replay screaming and crying with joy when Frank secured the kimura and the fight was stopped. On February 2, 2008, at UFC 81, Mir welcomed former WWE wrestler Brock Lesnar to the octagon for Lesnar's highly anticipated debut. It took Lesnar less than 10 seconds to shoot for a takedown and muscle Mir to the mat. However, seconds after Lesnar began to unload strikes from Mir's half guard, referee Steve Mazzagatti controversially deemed that there were some illegal punches landed to the back of Mir's head, drawing a foul and a one-point deduction. The fighters were ordered to stand up, and Mir was given a brief recovery period. As the fight resumed, Mir was almost instantly dropped with a big punch from Lesnar. Lesnar continued to land punches on Mir and shucked off Mir's armbar attempt before moving to a stacked guard. It was here that Mir caught Lesnar with a kneebar, causing