Speed plus mass equals destruction.

Brock Lesnar was talking about punching power when he used that simple equation during a recent conference call. But it's also a pretty good explanation for to how Lesnar has gotten a shot at Randy Couture's heavyweight title in just his third Ultimate Fighting Championship bout.

The former Bismarck State College wrestling champ has shown an unmatched combination of strength and agility in his brief mixed martial arts career. Combine that with the fame he gained during his pro wrestling career, and Lesnar has become perhaps the sport's top drawing card.

The question of whether Lesnar has realized enough of that tantalizing potential to take Couture's belt will be answered tonight in the main event of UFC 91 in Las Vegas. The bout, which UFC president Dana White said is likely to be the biggest in MMA history, is available on pay-per-view.

Lensar believes he is ready.

"Well, there hasn't been (anything) that I haven't covered," Lesnar said. "… So I'm prepared for just about anything that Randy Couture has to offer. And I hope that he brings everything, including the kitchen sink."

As a five-time UFC champion, Couture, 45, is considered a legendary figure in MMA, as his nicknames - "The Natural" and "Captain America" - suggest. He has already been inducted into the UFC Hall of Fame. Yet opinion on the fight is sharply divided, and it is Lesnar - due to his youth and incredible athletic ability - who is a slight betting favorite.

Couture (16-8), has made a career of overcoming the odds, scoring bigger upsets against the likes of Chuck Liddell and Tim Sylvia. He said he can draw on that in the Lesnar bout.

"Well, I definitely think that that experience in having been in a lot of those situations is an asset and something to rely on," Couture said. "It didn't matter what combative sport you're involved in. They are sports of experience. … I've been in a lot of different situations, and, you know, those all count."

The 31-year-old Lesnar was a national champion at BSC, then again at the University of Minnesota. But his pool of MMA experience isn't nearly as deep. Lesnar had a quick stoppage of Min Soo-Kim for another organization, a nearly as fast submission loss to former UFC champ Frank Mir - a fight Lesnar dominated up until that point - and his destruction of Heath Herring.

"I will have to say I'm more confident on my feet now and confident on the bottom and just all around," Lesnar said. "… Coming off a win from Heath, you know, my confidence level is through the roof, but at the same time we're staying grounded, too."

"… I've pushed myself to the farthest extremes in this camp because I'm not fighting a slouch, and I know that."

Couture was an All-American wrestler at Oklahoma State University and a four-time national champion in Greco-Roman. As such, he is the first elite wrestler Lesnar will face in the octagon. Couture is not the submissions expert that Mir is, but he presumably has an edge on Lesnar in jiu jitsu.

Couture's standup skills are more polished, but Lesnar has shown startling punching power. He finished Kim with strikes and took Mir and Herring off their feet with single punches. Both those fighters outweigh Couture by 30 pounds.

At 220 pounds, Couture will likely be giving away 50 pounds to Lesnar by fight time. Though he has worked out with large wrestlers to prepare for Lesnar, simulating Lesnar's athletic ability is another matter.

"I think I'm a pretty fair athlete myself," Couture said. "I move fairly well. Brock's a big, strong and explosive guy, but (I certainly) don't want to stand around in front of him."

In his preparation, Lesnar said he has studied all of Couture's fights.

"We're pushing this fight to the limit, and I don't feel threatened by anything that Randy's done. …We've covered every aspect of his game," Lesnar said. "I don't work on avoiding any situation, because anything can happen in a fight and even in a wrestling match. So, we don't avoid situations. We learn how to control them."

Except for the final seconds of the Mir fight, Lesnar has done that in each of his bouts, to the extent that he has yet to take a hard punch. If he can do the same tonight, he will become UFC champ.

"It's a great opportunity for the both of us," Lesnar said. "Hopefully, Randy is getting well-compensated and … hopefully it's a win-win for everybody. But like I said before, I'm coming to win this fight. And that's the bottom line."