Khan ready for his U.S. close-up

But in truth, Americans first became aware of Khan in September 2008, through a grainy, 58-second YouTube video that the British boxer would prefer was never transmitted across the pond. The footage was of Khan's junior welterweight showdown against heavy-handed Colombian BreidisPrescott. At the time, Khan was a rising prospect with an unblemished record and a seemingly limitless potential. Though also undefeated, Prescott was viewed as a stepping-stone opponent, a physical brawler who could give Khan a few extra rounds before he moved on to a more legitimate contender.

Unfortunately for Khan (22-1, 16 KOs), that perception was far from reality. When the opening bell rang Khan rushed Prescott, snapping off sharp jabs that connected to Prescott's skull. But Khan also extended his neck out like a giraffe with every swing -- and Prescott took advantage. He wobbled Khan with a crushing left hook 22 seconds into the round and dropped with another equally savage left three seconds later. Loose legged and rattled, Khan beat the count but ate another left hook seconds later, putting him down for good.

"He caught me with some good shots," Khan said. "I didn't think he could hurt me like that."

Suddenly, Khan's bright future was clouded with uncertainty. A fighter's chin is the attribute that often defines him and Khan's had been exposed as one consisting of shattered glass.

Three days after the loss Khan gathered his team together. During a six-hour meeting, the boxer declared his desire for significant changes. First to go was trainer Jorge Rubio. His replacement: Freddie Roach.

"When I put him on the stool after the Prescott fight, he didn't know where he was," said Khan's manager, Asif Vali. "But in those minutes I think he became a man. He realized boxing is a serious business and he needed to take it seriously. And to do that, he said he wanted to work with Freddie."

Khan first met Roach in 2005, during a tour of several notable U.S. boxing gyms. And he instantly took a shine to Roach's Wild Card gym, a steamy torture chamber where laziness is an unforgivable sin.

Roach saw the talent. He saw the quick hands and cat-like reflexes. But he also saw an impatient fighter who didn't put together enough combinations and led with his jaw.

"He made a lot of stupid mistakes," Roach said. "Against Prescott, he caused the knockout. With his chin out like that, if I had hit him he would have gone down."

Along with retooling his game, Roach wanted to re-sculpt Khan's body. Years of working out in the U.K. with rugby players doing tire work and sled drills had made Khan top-heavy and unbalanced. To that end, Roach tasked strength coach Alex Ariza with reshaping Khan's physique.

"When he first came to us, he was just developed so wrong," Ariza said. "The had this massive upper body and small legs. We had to take some of that mass away."

Ariza and Roach quickly designed Khan's workout program. Plyometrics, sprinting and "a whole lot of water work," said Ariza became part of Khan's daily routine. In the mornings Khan would rise at 5 a.m. and join Roach's other fighters -- including Manny Pacquiao -- running four miles through the steep hills of Griffith Park. Ariza would mix in ladder drills as well as dead runs up the stairs at the Santa Monica beaches and the sand dunes in Redondo Beach.

"Ariza is an animal," Vali said. "There are no cutting corners with him. You do it proper, or you do it again.

"There were a lot of days I could tell he didn't really like me," Ariza said. "But he doesn't complain. And he's an exceptional worker."

Ariza also changed Kahn's diet, cutting out the starch-filled foods and replacing them with a daily dose of fish, chicken, eggs, meat and dairy products. For most of his career, Khan resisted drinking too much water, feeling it added unnecessary weight to his 5-foot-10 frame. Ariza ordered him to guzzle it by the gallons.

"For some reason a lot of these guys never drink water," said Ariza. "It was the same with Manny. But drinking that much water actually helps with weight loss."

Back in the gym, Roach set his sights on repairing another potential problem. Too many times Roach had seen a brutal knockout level a fighter's confidence. So Roach shoved Khan right into the ring with Pacquiao and put the same $1,000-per-knockdown bounty on Khan's head that Pacquiao's sparring partners chased after.

"I've seen him take some really big shots," said Ariza. "You have to understand, every day is a championship fight for some of these guys. They are trying to catch Freddie's eye. [Amir] is in full-on wars in the ring."

It didn't take long for the work to pay off. In his first fight under Roach, Khan knocked out journeyman Oisin Fagan. He followed that up with a technical decision over aging legend Marco Antonio Barrera. Last July, Khan claimed his first world title when he outpointed Andiry Kotelnik.

"That Kotelnik fight was his first time we really challenged him," said Ariza. "I'd get him up a half-hour earlier and put him through some of the worst things you could come up with trying to mentally break him. But he was strong and he went out and dominated a really good fighter."

On Saturday, Khan, 23, has a new challenge in Malignaggi. It's no secret the sharp-tongued Malignaggi (27-3, 5 KOs) was hand-picked because of his lack of punching power. Khan is expected to win. But he was also expected to beat Prescott, which is why Khan hasn't cut any corners preparing for his U.S. debut.

"Amir understands that another defeat will push him down the ladder," Vali said. "But he's a much smarter fighter than he used to be. He thinks the fight a lot more. He thinks about his opponent. It's what will make him a great champion."