The Ultimate Fighting Championship on Monday finally made official the main event for UFC 106 scheduled for Nov. 21 at the Mandalay Bay Events Center in Las Vegas.

As reported by MMAWeekly.com, UFC heavyweight champion Brock Lesnar will defend his title against rising contender Shane Carwin. Also featured at UFC 106: Lesnar vs. Carwin is a light heavyweight bout featuring the return of former champion Tito Ortiz, who squares up with first-ever UFC heavyweight champion Mark Coleman.

"Brock Lesnar has been tearing through everyone over the last year," said UFC president Dana White on UFC.com. "But in Shane Carwin, he's not only fighting someone as big as he is, he's fighting someone who has ended all of his fights in less than three minutes. This is literally the biggest heavyweight title fight ever and may also be the most explosive."

Lesnar (4-1) was submitted by Frank Mir in his Octagon debut, but exacted revenge at UFC 100 where he crushed Mir with a second round TKO. He also manhandled both Heath Herring and Randy Couture to capture the title at UFC 91. He is an anomaly in the sport with only five bouts to his credit, winning the championship in his fourth.

"I'm excited to get back in the Octagon on Nov. 21 to defend my title," Lesnar said. "I'm looking forward to fighting Shane Carwin. He's undefeated and I'm the man who is going to put an end to that."

A resident of Broomfield, Colo., Carwin has been on a more impressive winning streak than Lesnar, though his opposition lacks some of the luster of Lesnar's resume. He has, however, racked up an overall record of 11-0, including three-straight in the UFC. None of Carwin's opponents have escaped the first round. His most recent action was a 69-second knockout of Gabriel Gonzaga at UFC 96.

"I was extremely excited when I got the news that I was fighting Brock," Carwin said. "I couldn't even sleep that night. This fight is going to be different for both of us. We're not used to facing someone who equals us in size. I can see this fight taking place everywhere. We both have wrestling backgrounds, but hopefully we'll get into some exchanges on the feet too."

Tito Ortiz had all but relegated himself to leaving the only promotion that he's ever really known until an unlikely reconciliation with White brought about his return.

"It's like a homecoming for me," Ortiz said. "The back is 100-percent and it's great to be returning to the UFC. Styles make fights and our styles are exactly the same. I expect a war and I expect more excitement from this match than anything else this year. There are a lot of people out there that expect me to succeed and there are a lot of people out there that expect me to fail. But I feel great and I'm expecting to win back my belt."

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