The action started with both fighters looking to use their strikes to set up a takedown. Pierce looked to take the fight to the ground, but Simpson was able to stop the attempt.
Simpson landed a right hand that appeared to rock Pierce and he had to grab the leg of Simpson to hold him off. With Pierce having one of his legs, Simpson landed several strikes to separate from Pierce.
After the fighters separated, Simpson landed a takedown and jumped on the back of Pierce. Simpson attempted to lock in a rear-naked choke, but Pierce would escape and the round would end.
At the start of the second round, the fighters started exchanging strikes and Pierce landed a right hand that dropped Simpson. With Simpson on the ground, Pierce landed a few more shots before the referee came in to stop the fight. This is Pierce first win by knockout since early 2011 and has now won two straight fights.
UFC on FX 5 Results:
Mike Pierce def. Aaron Simpson via KO (strikes) – Round 2, :29
Marcus LeVesseur def. Carlo Prater via split decision (29-28, 28-29, 29-28)
Jacob Volkmann def. Shane Roller via submission (rear-naked choke) – Round 1, 2:38
Diego Nunes def. Bart Palaszewski via unanimous decision (30-27, 29-28, 30-27)
Darren Uyenoyama def. Phil Harris via submission (rear-naked choke) – Round 2, 3:38