Benji Madden was a real knockout in Vegas last Saturday. The "Good Charlotte" singer beat MTV host Riki Rachtman in a celeb boxing match ... in less than two minutes.
According to People, Rachtman said, "I got wasted by the guy in Good Charlotte."
After the fight -- which took place at the Hard Rock Hotel -- Paris Hilton's ex-BF was spotted leaving hand-in-hand with Playboy Playmate Holly Madison.