Penn, so everyone wondered how he would respond in his next bout back at 155, especially considering that Sanchez promised to take Penn into the late rounds and simply outwork him en route to taking the title. Penn, a little more low-key than usual leading up to the bout, took everything in and then unleashed it on fight night, putting on one of his best performances in dominating Sanchez before finishing him in the fifth round. Cardio? The Prodigy had plenty. Matt Hughes III -- November 20, 2010 -- UFC 123 Result -- Penn KO1 The win over Sanchez would be Penn's last as lightweight champion, as he lost a razor-thin decision to Frankie Edgar at UFC 112 in April of 2010 and then a more lopsided verdict in their rematch in August of that year. Undeterred, Penn surprised many when he revealed that he was moving back to 170, and his first opponent at UFC 123 would be none other than his old nemesis Hughes. In the rubber match though, Penn took care of business quickly, knocking the Hall of Famer out in just 21 seconds. When it was over, it was shades of the first Uno fight, as Penn sprinted out of the Octagon before returning for the official announcements. As he said after the bout, "I've been trying to do a fight like the (first) Uno fight for the last nine years and it just never came out that way. So when this fight (with Hughes) ended