LOS ANGELES — A lot has changed in the heavyweight world since Lennox Lewis put a whipping on Mike Tyson a year ago in Memphis.

There are two intriguing new belt holders, one big deflated contender and no sign of Tyson.

One thing that hasn't changed: Despite his layoff and his tendency to give his titles away, Lewis is the true heavyweight champion until somebody beats him in the ring.

"I am the last great heavyweight," Lewis said.

That boast gets put to the test tonight when a giant from Ukraine tests both the rusting skills of Lewis and his suspect chin in the first heavyweight title fight in Los Angeles in 45 years.

Vitali Klitschko wasn't even supposed to be the best of two fighting brothers. But the awkward 6-foot-7 contender got two weeks notice and the biggest chance of his boxing life and couldn't pass it up.

"I am not a god and nobody is perfect," Klitschko said. "But I am really confident to go in the ring. I've been waiting a long time to fight Lewis."

Lewis, who will be punching up to reach his opponent for one of the few times in his career, is a 4-1 favorite to defend his WBC heavyweight title against the No. 1 contender in a scheduled 12-round fight at Staples Center. The fight will be televised by HBO, beginning about 8:30 p.m. MDT.

It's a lot different than last June, when a bigger, faster Lewis battered Tyson around the ring before finally stopping him in the eighth round of the richest heavyweight fight of all time.

Since then, Lewis (40-2-1, 3 knockouts) has been relaxing and enjoying himself as the heavyweight division changed about him. Roy Jones Jr. won a title and so did Chris Byrd, while Klitschko's brother, Wladimir, was exposed in a shocking knockout loss to Corrie Sanders.

Still, the heavyweight championship belongs to Lewis until he loses or decides to give it up. He was once the undisputed champion, but gave up the IBF belt rather than fight Byrd and the WBA belt so he wouldn't have to fight John Ruiz.

Klitschko, for one, believes, the 37-year-old Lewis would have been better served to retire on top after his impressive performance against Tyson.

"He decided to fight again. In my opinion, it is a mistake," Klitschko said.

Lewis was planning to fight Kirk Johnson in a bout that generated nothing but yawns. Johnson was injured in training, though, and he reached out to Klitschko, who was training to be on Saturday night's card anyway.

To keep his WBC title, Lewis had to fight Klitschko (32-1, 31 knockouts) by the end of the year. By fighting him now, he leaves open the possibility of a big money fight later this year against Jones.

"Jones would be a natural finish for my career if he dares to test it," Lewis said. "There would be so much money involved in fighting me, but people go funny over money."

Lewis will make a lot of it Saturday night, getting a reported payday of some $10 million for the title defense. He claims to be reinvigorated and ready to fight again, but he weighed in Thursday at 256 1/2 pounds, seven pounds heavier than when he fought Tyson and the heaviest weight of his career.

"He is a big man, a solid man who is about normal weight-wise for a guy his size and age," Lewis trainer Emanuel Steward said. "Believe me, Lennox is in great shape. He has sparred over 100 rounds. If he had come in at 250 pounds I would have been upset. What he weighs will not be a factor Saturday."

Klitschko, whose only loss came when he quit with a shoulder injury against Byrd in a fight he was winning, got some help in training from his brother, who acted in boxing scenes with Lewis in the movie "Oceans 11."

He'll need all the help he can get handling a veteran heavyweight champion whose chin may be suspect but who seems to rise to the occasion in fights he really wants.

"Lennox Lewis is very skilled, but nobody is perfect and I have seen some weaknesses," Klitschko said. "I know I am the underdog, but I will surprise people on Saturday night."

The 31-year-old Klitschko, who learned to box in the Soviet Union amateur system and has had most of his fights in Germany, hasn't faced nearly the top-quality opposition that Lewis has.

He's big and awkward, fights standing straight up and seems easy to hit. But he has a big overhead right hand that has helped him get 31 knockouts in 33 fights.

"My style is very unorthodox. It looks not so nice maybe when watching fights outside," Klitschko said. "It may not be smooth and nice technical style, but the result is very effective."

Lewis said the style is also very inviting.

"Vitali said he's seen some weaknesses in me; I've seen a whole heap of weaknesses in him," Lewis said.

The fight is the first heavyweight title fight in Los Angeles since Floyd Patterson defended his title with a 13th round knockout over Roy Harris on Aug. 8, 1958, at the old Wrigley Field.

Harris, it turns out, was somewhat overblown, if not colorful, contender. Lewis thinks the same about Klitschko.

"He has bitten off more than he can chew," Lewis said. "He wanted this so much. Like they say, be careful what you wish for. He wished for this fight, and this is what he is going to get."