Hilo's BJ Penn successfully defended his UFC lightweight world championship defeating Sean Sherk tonight in Las Vegas.

The referees called the fight at the end of the third round when Sherk appeared dazed and was bleeding from a cut under his right eye from Penn's punches.

The fight was the main event of the UFC 84 "Ill Will" mixed martial arts card at the MGM Grand Garden Arena.

Penn improved to 13-4-1. Sherk is 32-3-1.

The fight was promoted as "a grudge match" by the UFC.

Last July, when Sherk tested positive for Nandrolone, which is a form of anabolic steroids. He was eventually suspended for six months, and stripped of the UFC lightweight championship. Penn defeated Joe Stevenson by choke submission in January to take the title.