Five years after winning a career-launching Olympic silver medal, Amir Khan has his first shot at a world title when he steps up to light-welterweight Saturday to fight WBA champion Andreas Kotelnik.

The big-punching Khan will be facing a Ukrainian opponent who has never been knocked down in his 34-fight professional career.

Khan (20-1) made an impact at the 2004 Athens Olympics as a 17-year-old and has shown his potential as a pro with a series of spectacular knockout victories.

But the Briton also revealed a suspect chin after being knocked out in 54 seconds by Breidis Prescott of Colombia last September.

The 22-year-old Khan has regrouped, however, switching trainers and relocating to the United States to rebuild his career.

"The Prescott fight made me change from a boy to a man. It took me out of my comfort zone because when you lose a fight you look at the mistakes and everything," Khan said. "I've changed everything. I've moved to train in Los Angeles, I'm totally focused now. I'm a different fighter, a different person and the way I fight now is totally different."

A fifth-round stoppage victory in March over respected veteran Marco Antonio Barrera helped repair Khan's credibility.

"I know people didn't think I'd become a world champion _ even people probably in my own camp, my own team," Khan said. "I made one mistake but I've proved everyone wrong by beating Barrera and now fighting for a world title. And hopefully when I wake up on Sunday morning, I'll be a world champion."

Khan is expecting a longer fight at M.E.N. Arena against Kotelnik, the lightweight silver medalist at the 2000 Sydney Olympics who has a 31-2 record with one draw since turning pro.

"It's going to be a skillful fight, more about technique, and I don't think it's going to finish early," he said.

Khan has fought once at light-welterweight, scoring a unanimous decision over Rachid Drilzane of France in December 2006.

Kotelnik has had two successful defenses since beating Gavin Rees in March 2008 to take the WBA belt, outpointing Norio Kimura and Marcos Rene Maidana.

"If I win this fight it will open the road to further fights, especially in America," Kotelnik said.