Chael Sonnen (Pictures) confirmed that he will face Paulo Filho (Pictures) on Sept. 10 for the World Extreme Cagefighting middleweight title. The WEC 37 event is currently scheduled for the Hard Rock Hotel & Casino in Las Vegas, but the WEC is considering a change of venue, possibly to a different state.

Filho beat the Oregonian in a controversial bout at WEC 31 last December. Sonnen dominated most of the first two rounds, but was caught in an armbar during the final seconds of the second. Although Sonnen denies tapping out, referee Josh Rosenthal stopped the fight.

"I want to be a world champion," Sonnen said. "I want to find out who the best is. If I find out confidently I can't make it to the top, I'll quit. If my goal backs off of winning a championship, I'll disappear from the sport and do something else."

They were scheduled for a rematch at WEC 33 in March, but Filho backed out - checking himself into a drug rehabilitation program instead. Sonnen earned a unanimous decision over Bryan Baker (Pictures) in the interim.

"He has a right to miss a date, especially for that type of issue," Sonnen said. "We should be supportive of him. If he starts to miss two or three, then there is a problem. But there is the potential there to set a good example."

However Sonnen's good will towards the Brazilian ended there. The two had a notable war of words before their first bout. Sonnen already fired the first shots.

"I wasn't trying to be a heel with Paulo (before the first fight), he's just a dirtbag in real life," he said. "The only reason I fought him is because no one else would.

"There is this idea of being respectful to other fighters. That's the new word. But this isn't Britney Spears insulting Christina Aguilera from halfway across the country through the media. I'm going to get in a cage and fight about it, so if he thinks I'm using fighting words -- it's because I'm planning to fight him."