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 received two weeks notice and the biggest chance of his boxing life and couldn’t pass it up.

“I’ve been waiting a long time to fight Lewis.” Klitschko said.

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 9:30 p.m.

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, 31 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 surrendered the IBF belt rather than fight Byrd and the WBA belt so he wouldn’t have to fight John Ruiz.

Klitschko 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 tonight’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 tonight, 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 2561/2 pounds, seven pounds heavier than when he fought Tyson.