Amir Khan says he'll outsmart bigger man Saul Alvarez

Amir Khan shadow boxes under the watchful eye of Golden Boy Promotions' Oscar De La Hoya in Hayward, California. Alexis Cuarezma/Getty Images

Amir Khan says brains and not brawn will see him pull off one of the biggest shocks in recent boxing history.

Khan, 29, has stepped up two weight divisions to face WBC world middleweight king Saul 'Canelo' Alvarez in Las Vegas on Saturday.

A former world light-welterweight champion, Khan has been stopped twice in three defeats and had scares in other scraps against smaller men than Canelo. But the bulked-up Briton says boxing clever with fast flurries of punches and avoiding toe-to-toe exchanges with the more powerful Canelo will see him upset the odds.

"It's the strongest I've been for any fight, having that little bit of extra weight can only give me that extra advantage in getting power but the speed is still there," said Khan. "All round I feel so much stronger as a fighter. I've sparred a lot of rounds with heavier guys and I've done a lot of strength work in my legs by training on sand to help with the later rounds.

"The speed is still there but this fight will be more mental -- I have to win it with my brains. I can't let my courage take over because it could get me in trouble, it has in the past, but I'm much smarter and wiser now."

Khan is expected to earn around £5 million for the bold move of taking on Canelo at a catchweight of 155 pounds. The Mexican -- whose nickname means cinnamon in Spanish after his red hair -- will be overwhelming favourite and has lost just once on points to Mayweather in 2013.

"I used to get involved in tear-ups and take risks, like I did against Marcos Maidana," Khan said. "But I haven't left myself open in my last few fights and relied on my skills to beat Chris Algieri, Devon Alexander and Luis Collazo on points.

"And that's how I see this fight going. I will be too smart and too fast for him. The more videos I see of Canelo the more confident I am I will win this fight and become middleweight world champion, which will be huge, it will be a massive shock to the world. But not to me because I believe I can win this world title.

The Bolton fighter may have missed out on big pay days against the likes of Floyd Mayweather Jr and Manny Pacquiao, both of whom snubbed him to box other opponents. But with those greats retired, Alvarez is now one of boxing's biggest global stars.

"I was chasing the Mayweather fight, the Pacquiao fight, and I really believe that if those fights happened they'd be easier than this fight," Khan added. "This fight will be more physical and it will be me using my brains even more, because with Canelo I cannot make any mistakes.

"This fight shows who I am and I think a lot of young fighters should take a page out of my book and fight the best fighters out there rather than avoiding a lot of people out there. It shows I'm not scared of anyone."