LAS VEGAS (AP) -- Nick Diaz moved back into title contention with a convincing unanimous decision victory over B.J. Penn in the main event at UFC 137 Saturday night. The first round was evenly matched with both fighters landed strikes from the start. Penn was able to take Diaz down to the mat briefly, landing a few strikes to gain the early edge. Diaz begain to land a number of strikes to the body and face in the second round. He taunted Penn and continued to land heavy strikes, dazing the former champion. "It felt good to be back fighting," Diaz said. "In the second round I turned it on and tried to take him out. Things would have been different if it were five rounds. I would have taken him out for sure in the fourth." It was more of the same in the third round with Diaz picking apart Penn at will, landing numerous combinations that left Penn's face swollen and bloodied. "B.J. is one of the best there is," Diaz added. "Not that many people would go out there and take all those punches."
All three judges scored the fight in Diaz's favor 29-28, 29-27 and 29-28.
After the fight, a battered Penn said: "Hats off to Nick Diaz, he's the man." He went on to say, "This is the last time you'll see me in here. I have a daughter and another on the way. I don't want to go home looking like this." Penn was the first non-Brazilian winner of the Jiu-Jitsu championships in the black belt catagory and only the second fighter in UFC history to win titles in two different weight classes. In the postfight press conference UFC president Dana White announced Diaz will next face current welterweight champion George St. Pierre. Diaz was originally scheduled to face St. Pierre for the title on this card but due to disciplinary actions Diaz was replaced by Carlos Condit. St. Pierre eventually pulled out of the fight against Condit due to injury. In the co-main event, Cheick Kongo defeated Matt Mitrione by unanimous decision. After an inactive first round by both fighters, Kongo opened up the second striking, landing multiple solid kicks to Mitrione's legs and body. Both came out swinging in the third round with Kongo landing a strike that sent Mitrione back to the cage. Kongo went for a takedown and ended up slamming Mitrione to the ground then landed a few shots that opened up a small cut and caused some swelling. Mitrione was able to make it back to his feet only to find himself on the mat after another takedown. Kongo controlled the action from the top using effective ground and pound to neutralize any counter from Mitrione. The judges scored the bout 30-27, 30-28, 29-28. "I wasn't sure how to react to Mitrione's movements in the beginning," Kongo said. "I was happy with my performance, especially my striking. I wanted to make him work. My game plan was to wait and see what he did." With the victory Kongo moves closer to a possible title shot. Earlier, Roy "Big Country" Nelson defeated Mirko Cro Cop by TKO due to strikes at 1:30 of the third round, sending the MMA legend home with a loss in what appears to be his final fight. Also, Scott Jorgensen earned a unanimous decision over Jeff Curran and Hatsu Hioki won a closely contested split-decision victory over George Roop. In the preliminary fights, Donald Cerrone forced Dennis Siver to tap at 2:22 of the first round and Bart Palaszewski knocked out Tyson Griffin in the first round. Brandon Vera, Ramsey Nijem, Francis Carmont and Clifford Starks all earned unanimous decision victories.