The Associated Press

LOS ANGELES - A lot has changed in the heavyweight world since Lennox Lewis whipped 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 away his titles, 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 the 6-foot-7 Vitali Klitschko tests both the rusting skills of Lewis and his suspect chin in the first heavyweight title fight in Los Angeles in 45 years.

"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 10:30 p.m.

Since last June, 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 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.

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.

WILLIAMS BOUT CANCELED: Olympic silver medalist Ricardo Williams Jr. (8-1 as a pro) will not fight as scheduled on the undercard of the Lewis-Klitschko match. The junior welterweight from Cincinnati was to have fought Rogelio Castaneda (19-6), said boxing manager Jimmy Montoya.

But some updated medical tests were not received in time by the California Boxing Commission, so the bout was canceled. Williams, who is continuing his training, hopes to land a match on ESPN in the next few weeks, said co-manager Buddy LaRosa.

--John Erardi