UFC 137 results and recap: Diaz calls out GSP, Penn and Cro Cop announce retirement

Nick Diaz took B.J. Penn to a brutal decision at UFC 137, winning what Penn said during his post-fight interview was The Prodigy’s last dance in the Octagon. “This was probably the last time you’ll see me in here. I can’t keep performing at the top level,” Penn said. “I’ve got a daughter and another daughter on the way. I …