UFC 137 results recap: A look back on another action-packed weekend in Las Vegas

It's all over!

Ultimate Fighting Championship (UFC) just wrapped another successful weekend campaign as UFC 137: "Penn vs. Diaz" came, saw and conquered the Mandalay Bay Event Center in Las Vegas, Nevada.

This event seemed doomed from the start, as it was plagued by injuries, disappearing acts and enough fight card changes to make mixed martial arts (MMA) fans' heads spin.

Luckily, the details were eventually worked out and the pieces fell into place.

The show must go on. And what a show it was. Though things started slow and even seemed stagnant at points, the main event made it all worthwhile.

After the jump, MMAmania.com examines the highlights of UFC 137 -- the good, the bad and the ugly:

In the main event, we saw Nick Diaz and B.J. Penn put on a fireworks-filled, bloody match up between two welterweights who desperately wanted a crack at Georges St. Pierre and his 170-pound belt.

Prior to the fight, Diaz admitted he was battling nerves because of the fact that "The Prodigy" has always been one of his heroes. The first round revealed some of Diaz's nerves and, for a few minutes, it looked like the Hawaiian was going to make quick work of the man who once had his poster up on his wall.

Not so fast.

In the second round, Diaz came out like a man on a mission, using precision striking to bludgeon the face of a fighter we've rarely even seen cut in previous fights.

Read a full recap of the B.J. Penn vs. Nick Diaz fight at UFC 137 here. 

When it was all said and done, Penn, battered and bruised, told Joe Rogan that he had entered the Octagon as a fighter for the very last time.

Diaz got on the microphone and called out the champion, St. Pierre, going as far as to accuse him of faking an injury to avoid having to fight.

As a result of Diaz's strong performance (and possibly his strong words), UFC president Dana White went back on his original plan to have "GSP" defend his belt against Carlos Condit and have the champion fight Diaz instead. The bout is rumored to be going down on Super Bowl weekend.

Watch video highlights from B.J. Penn vs. Nick Diaz UFC 137 fight right here.

Penn wasn't the only fighter to hang up the gloves after his fight. After losing badly to fellow heavyweight Roy Nelson, renowned head kick specialist Mirko Filipovic announced that we had seen the last of "Cro Cop."

Matt Mitrione was unable to get past the heavyweight divisional gatekeeper as Cheick Kongo proved to be too seasoned and experienced for "Meathead" to overcome.

Donald Cerrone catapulted himself right into the lightweight division title mix by violently stopping Dennis Siver in a bout that left the German kickboxing specialist asking for the license plate of the truck that hit him.

Hatsu Hioki made a triumphant UFC debut with a very controversial decision win over George Roop. Afterward, he proclaimed that Japanese MMA is not dead. (Apparently, it was just taking a little nap.)

Enough from us. What was your favorite UFC 137 highlight, Maniacs?

For complete UFC 137 results and a detailed recap of all the action click here. To check out a recap of the UFC 137 fights that were streamed online via Facebook click here. Want to know what happened on the UFC 137 "Prelims" portion of the card? To read a full recap click here and here.

And just in case you want to get up to speed on the entire UFC 137 fight card from top to bottom click here.