Mirko Filipovic, 37, retiring after loss

LAS VEGAS -- Mirko Filipovic, one of the most iconic figures in mixed martial arts history, announced his retirement Saturday at the age of 37.

The Croatian fighter made the decision immediately following a TKO loss to Roy Nelson in the third round of their heavyweight bout at UFC 137 in Las Vegas.

Filipovic, who also competed as a professional kickboxer and amateur boxer, retires with a professional MMA record of 27-10-2.

"The UFC has been so good to me over the years and it is hard to leave this company and this sport," Filipovic said.

Known to fans as "Cro Cop," Filipovic made his MMA debut at a K-1 event in August 2001. He built his legacy in the now-defunct Pride Fighting Championships, where he won the open-weight Grand Prix in 2006 with a stoppage win over Josh Barnett.

He made his UFC debut in February 2007, scoring a first-round TKO over Eddie Sanchez at UFC 67. He went on to compete in 10 total UFC bouts, compiling a record of 4-6. He lost his final three fights, all via knockout.

"Even though I didn't do as well in the UFC as the rest of my career, I feel like I did everything that I could to have an overall successful career," he said.

Filipovic had his moments in Saturday's fight, hurting Nelson badly with a combination midway through the second round.

Nelson (16-6) eventually would recover and finish the fight, but offered his opinion that Filipovic was certainly capable of fighting again if he wanted to.

"He came to bang," Nelson said. "If he didn't want to retire, he could still fight. He's still one of those guys who can hit hard. He's very competitive."

Filipvoc left the arena quickly following the loss and was not available for further comment. UFC president Dana White commended him, however, on a strong performance and a memorable career.

"Cro Cop has been a good guy since the day we signed him," White said. "He's a warrior and he's done a ton of good things for the sport.

"He's very disappointed with his run in the UFC. But (to be his age) and still be out there fighting with guys who are younger and faster and more explosive than you are -- he came out and did what he said he was going to do. At the press conference, he said, 'I'm going to give you guys a fight whether I win or lose.' "

Brett Okamoto covers mixed martial arts for ESPN.com. Follow him on Twitter.