LAS VEGAS Dec 11: Vitali Klitschko tries to make his claim to be the legitimate heavyweight champion when he defends his WBC title for the first time against Danny Williams, who made a name for himself by beating Mike Tyson.

A spectacular performance by either on Saturday could vault the winner to the top of a pack of otherwise undistinguished heavyweight champions. Both realize what is at stake in the heaviest heavyweight title fight ever.

"It is very important that I win this fight," Klitschko said. "I know it will not be easy and I am prepared for that. But I know I must win."

Klitschko (34-2, 33 knockouts) defends the title he won in April against Corrie Sanders for the first time against Williams, who just 11 months ago was licking his wounds after losing the British heavyweight title to a journeyman named Michael Sprott.

Williams was plucked from obscurity to be Tyson's comeback opponent in July, then shocked everyone by weathering a storm from Tyson and coming back to knock him out in the fourth round.

His reward for the win was not merely financial. Wanting to strike while the Tyson win was still fresh in the minds of boxing fans, Klitschko's promoters picked him for the champion's first title defense.

"Danny Williams destroyed my dream of fighting Mike Tyson," Klitschko said. "Now I will destroy his dream of being the heavyweight champion."

Oddsmakers like Klitschko's chances, making him a 4-1 favorite in the fight at the Mandalay Bay hotel-casino. Neither fighter will have any trouble finding the other in the 20-foot (6-meter) ring. The 6-foot-7 (2.01-meter) Klitschko weighed in at 250 pounds (112.5 kilograms) on Thursday, while the 6-foot-2 (1.88-meter) Williams was 270 pounds (121.5 kilograms).

The combined weights break the record for the heaviest title fight ever set by Klitschko and Lennox Lewis when they met in June 2003 in a fight Klitschko was winning before being stopped by cuts after six rounds.

Williams (32-3, 27 knockouts) has watched tapes of that fight and knows he must find a way to get inside and take the fight to a heavyweight who still carries the unorthodox Eastern European style he grew up with in Ukraine.

"The plan is to box him inside and get close," Williams said. "He's never been knocked down so I believe he's got a good chin. I'm hoping to get low and get inside on him and test that chin."

Williams, who has fought mostly in England, credits psychological development for his stunning success against Tyson. Before fighting Tyson, he often froze up before fights, sometimes even crying in his dressing room before going out into the ring. After losing to Sprott, though, Williams said he told himself to quit worrying about how he did and just fight. It paid off with two knockout wins and then his upset of Tyson. "I always believed I was the best heavyweight in the world," Williams said. +But I couldn't express it in the ring because I used to put too much pressure on myself." Williams may have also discovered something in his fight against Tyson that will give him comfort against the big-hitting Klitschko. Williams took everything Tyson had for the first two rounds without going down, then had enough left to finish off the former heavyweight champion.

"The key is hunger and desire. I have tremendous hunger and I am a warrior," Williams said. "You saw that in the Tyson fight. I showed a tremendous chin. These are the things that it will take to beat Klitschko."

One sideline to the fight is the turmoil in Klitschko's native Ukraine over the disputed presidential election. Klitschko said he nearly pulled out of the fight two weeks ago to return home and support democracy, but was persuaded that he could do more for his cause by fighting. The fight will be televised live in Ukraine in the early morning hours, and Klitschko plans to fly to Kiev on Sunday to help campaign for a second vote on Dec. 26.

"I am sportsman, not politician, but I am a citizen and not passive about what happens in my country," said Klitschko, who now lives in Los Angeles. "I don't want to make a speech in the ring. I want to fight and make a good result for my country."-AP