White announced that Penn would stay at lightweight to fight current UFC Lightweight Champion Sean Sherk. However, Sean Sherk subsequently was suspended by the California State Athletic Commission, and the status of the possible title fight was left in limbo as he pursued his appeals. With Sherk's title status still in limbo after months of hearings, the UFC scheduled Penn to fight Joe Stevenson at UFC 80 on January 19, 2008, for an interim lightweight title. The subsequent final decision by the California State Athletic Commission, which did not overturn Sherk's suspension, led to the title being stripped from Sherk and the Penn-Stevenson fight being upgraded to a full title bout, with the winner facing Sherk in their first defense. Lightweight Championship Penn knocked Stevenson down seconds into the first round with a right uppercut, then took Stevenson down, delivering a well placed elbow from the top position that inflicted a serious cut near Stevenson's hairline. In the second round, Stevenson fought more aggressively but was still unable to threaten Penn. Penn worked to back mount and defeated him by rear naked choke at 4:02 of the second round to win the Lightweight Championship. He celebrated the win by licking Joe Stevenson's blood off of his gloves. The win for Penn was awarded Beatdown of the Year by Sherdog for 2008. With this win, Penn became the second man (after Randy Couture) to win UFC titles in two different weight classes. On May 24, 2008, at UFC 84 at the MGM Grand Garden Arena in Las Vegas, Nevada, Penn fought former champion Sean Sherk in his first title defense bout. The fight was billed by color commentator Mike Goldberg as the "biggest fight in the history of the UFC lightweight division". Sherk attempted to take Penn down only once (in the first round), instead the fighters traded punches and leg kicks for the remainder of the fight. Penn landed jabs several times, utilizing his reach advantage over Sherk. In the closing seconds of the third round, Penn threw a punch and a hook that backed Sherk into the cage. Sherk then ducked under another punch – possibly to shoot for a takedown – when he was hit in the head by a flush flying left knee from Penn. Sherk went down and Penn continued with strikes, but the round ended before the referee stopped the fight. However, Sherk was unable