Against Wladimir Klitschko, Tony Thompson looking to score monumental upset Still, in the twilight of his career, Thompson continues to train with the vigor of an athlete far younger as he approaches what is virtually certain to be his last title fight. Even if he loses Saturday's rematch against unified world heavyweight champion Wladimir Klitschko (57-3, 50 knockouts) in Berne, Switzerland, Thompson won't leave the ring at Stade de Suisse deliberating if a lack of stamina and fitness contributed to his downfall. Klitschko "is in wonderful shape, and if you can't match that conditioning, you have no chance," Thompson said. Guys don't get too many more shots at the heavyweight championship [at Thompson's age]. The truth is, and I'm not trying to be funny, the truth to me is I'll beat anyone [else] in the heavyweight division. I have to beat the champion. I have to see if I'm on that level. In their first fight on July 12, 2008, in Hamburg, Thompson (36-2, 24 KOs) weighed in at 2471 / 2 pounds, and the fitter Klitschko, at 241 pounds, was able to land a clean right hand in the 11th round that sent his Silver Spring-born challenger to the canvas. Thompson had allowed his left side to be exposed after reaching and missing with a left jab, leaving Klitschko plenty of room to connect. The knockdown meant Klitschko retained the International Boxing Federation, World Boxing Organization and International Boxing Organization belts. It also dealt Thompson the second loss of his career and his first in more than eight years. A sore right knee was partly to blame, Thompson said. He was unsure of the precise nature of the injury before the bout, but medical examinations later revealed a torn meniscus. Even longtime trainer Barry Hunter was unaware until during the fight. You see how small he is? Hunter said, referring to Thompson's leaner physique heading into the rematch. He's smaller. He's faster. Like I said, all these are factors in this fight. If you can go in there and stay focused and disciplined and don't give me any more secret plans, we can go shock the world one more time this year. A Thompson victory would be in line with Buster Douglas stunning then-undefeated Mike Tyson in Tokyo in 1990. Douglas was a 42-1 underdog before knocking down Tyson for the first time in the undisputed champion's career with 1:22 left in the 10th round. Thompson is listed by some oddsmakers as a 50-1 underdog against Klitschko, as he bids to become the first American heavyweight champion since 2007, when Shannon Briggs captured the WBO title. There hasn't been a unified American heavyweight champion since Hasim Rahman owned the IBF and World Boxing Council belts in 2001. "I'm expecting Tony Thompson to be as aggressive as possible because that's his last chance for sure to fight for a championship," Klitschko said during a conference call last week. And I think Tony Thompson knows it pretty well. I think he knows it better than anyone else. Klitschko has won six fights in a row since beating Thompson. Five of those have been via either knockout or because his opponent failed to answer the bell. Among those victims was Rahman, who lost by TKO during the seventh round in Klitschko's first fight after dispatching Thompson. Thompson, meantime, has had five fights, all TKO victories, since his first bout with Klitschko. Thompson most recently scored a third-round TKO over Maurice Harris in an IBF heavyweight title eliminator to mandate the rematch with Klitschko, who has made no secret he'd prefer to fight a first-time opponent rather than Thompson. It's not a little bit of a chance. It's my last chance," Thompson said. I realize not a lot of TV channels want to put me on for whatever reason. Doesn't matter why. It's just a reality of the situation. The only way I can change that is win.