Penn was already a world champion in Brazilian Jiu-Jitsu. In fact he became the first American to win in the black belt level at the World Jiu-Jitsu Championships.
Penn won his first fight by TKO though, and would go on to win his next two by knockout, all in the same round.
He truly was a prodigy.
Penn fought another prodigy tonight in 23-year-old Rory MacDonald, and showed that he just may not be able to hang with the younger breed.
B.J. Penn as he is known all across the world, came out with the same intense look in his face that he has always had right before he quickly KO's an opponent.
But after going just 1-4-1 in his last six fights, it is time for Penn to hang up the gloves.
Penn is not just one of the greatest lightweights in MMA history. He is one of the greatest fighters that the sport has ever seen.
Besides Randy Couture, Penn is the only other fighter to capture UFC titles in two different weight classes.
Although he may feel he has something left to prove, Penn does not.
He will be a UFC Hall of Famer and could even be a great ambassador for the sport.
But after taking beat-downs in his last two fights against MacDonald and Nick Diaz, it is time for Penn to walk away for good.