By Ryan Burton

Amir Khan unveiled his new middleweight physique by topping the scales at 155lbs ahead of his fight with WBC champion Saul Alvarez.

The Mexican who did not show the expected size advantage over the challenger who is fighting beyond the welterweight division for the first time in his career, also weighed in at 155lbs.

By the time the two fighters have rehydrated ahead of Saturday's fight at Las Vegas' new T-Mobile Arena, Alvarez is expected to be around a stone heavier than Khan - who is likely to remain light to maximise his superior mobility and speed.

However, the 29-year-old did appear convincing two divisions above his natural weight, and not the uncomfortably-small figure some had feared he would be.

"It's a big challenge," said Khan. "I've had people like (Andre) Ward and (Andre) Berto pushing me in camp.

"I'm focused. Being the underdog this time, I want to prove I belong at the top."

Alvarez, 25, said: "I know I'm fighting a fast fighter who moves a lot, with a lot of experience, but I've prepared myself."