But Couture seems to thrive as the undersized and UFC betting underdog. Just ask Tim Sylvia and Gabriel Gonzaga, who both endured an ass whooping as UFC wagering favorites delivered by the much smaller Couture.

Couture entered the Octagon at 6' 2", 220 pounds and the +110 MMA betting underdog at UFC 68 on March 3, 2007 looking to reclaim his title against an enormous 6' 8'' and 268-pound Maine-iac named Silva who wore the belt, priced at -135 at BetPhoenix.com. 

For 25 minutes the two went to war in what was one of the best fights in UFC history. What the 45-year-old Couture lacked in size, he made up for with determination and raw fighting skills. Couture initiated the striking as the aggressor, taking Sylvia to the ground in the first round clearly frustrating the Maine-iac. In the best fight of his Hall of Fame career, Couture dominated throughout much of the bout to score an unanimous decision victory for his third championship.

In his first title defense at UFC 74 on August 25, 2007, the 220-pound heavyweight champion again entered the Octagon undersized and the +115 online MMA wagering underdog versus 6' 1'' and 242-pound Gonzaga. Having the ground game as a powerful Jiu-Jitsu ace, which Silva lacked, and coming off a devastating head kick that knocked out heavily favored Mirko Cro Cop, many believed Gonzaga would be the man to end Couture’s run at the top of the heavyweight division.

Instead, the champion came out and broke Gonzaga’s nose, and controlled the bout until 1:37 of the third round, when Couture posted a technical knock out, which he claimed with an arm broken by one of Gonzaga’s deadly kicks suffered earlier in the fight.

Following two successful title defenses and with two fights remaining on his UFC contract, Couture walked away from the world's top MMA series in October of 2007, because of contentious relations between himself and the organization. But in August, the heavyweight champion and the organization worked on a renegotiation of his contract that will enable Couture to finish his career with the UFC.

Shortly after the agreement was reached, UFC President Dana White announced the return to the Octagon of heavyweight champion Couture to face Lesnar in the main event of UFC 91 in Sin City. When the champion faces Lesnar, not only will he once again be the smaller fighter, Couture will also again be the slight online UFC betting underdog at -105, with the challenger priced at -125 in BetPhoenix.com UFC odds.

Despite being able to look the former WWE star in the eye, Couture will likely give away more than 45 pounds. Lesnar, was a former NCAA Division I National Wrestling Champion, and also performed as a pro wrestler that was an athletic freak who often performed eye-popping physical feats including his signature move, the F-5, which called for him to spin some massive opponent in the air before dropping him like a rag doll.

Lesnar's departure from pro wrestling to compete in the UFC earlier this year rocked the MMA world. His record is just 2-1 but his spectacular victory over Heath Herring at UFC 87 in August, has made this a highly-anticipated heavyweight title fight. Despite his size, Lesnar is quick and athletic and has wrestling skills equal of Couture’s who owns a 16-8-0 MMA record.

If you bet on UFC action, this is a very intriguing matchup, as Couture puts his heavyweight title on the line against the biggest opponent of his career, powerhouse Lesnar. Also on the card, Kenny Florian vs. Joe Stevenson; Amir Sadollah vs. Nick Catone; Gabriel Gonzaga vs. Josh Hendricks and Nate Quarry vs. Demian Maia.