UFC PPV Events: Season 2011, Episode 13

2011 - 13: UFC 137: Penn vs. Diaz

UFC 137 features the return of top ranked welterweight Nick Diaz, as he faces former two-division UFC champion BJ Penn. Plus two heavyweight matchups are on tap, as Cheick Kongo meets Matt Mitrione, and Mirko Cro Cop takes on Roy Nelson.