The news of Amir Khan’s decision to take on Saul ‘Canelo’ Alvarez was met with widespread shock due to the weight disparity between them.

The eight pounds represents a jump of two weight classes and victory will go down as one of the biggest shocks in British boxing history.

But Khan should take heart from the old adage that ‘it’s not how big you are but how good you are’ – and many have proven it in the past.

SUGAR RAY LEONARD v MARVIN HAGLER – April 6, 1987

Canelo’s promoter Oscar De La Hoya has likened Saturday’s fight to the famous 1987 meeting between Sugar Ray Leonard and Marvin Hagler, which took place just down the strip at Caesars Palace. Leonard came out of retirement to challenge Hagler for the very same WBC middleweight title that Khan fights for at the weekend, and beat the bigger man with a 12-round split decision.

MANNY PACQUIAO v OSCAR DE LA HOYA – December 6, 2008

Filipino icon Pacquiao had defended his lightweight title in June 2008 but jumped up two weight divisions to face Oscar De La Hoya just six months later. De La Hoya himself has dropped down from light-middleweight to take on the much smaller man, but he was battered into an eighth-round retirement by Pacquiao. The ‘Golden Boy’ never boxed again.

DAVID HAYE v NIKOLAI VALUEV – November 7, 2009

There was a huge 99lb weight difference when former unified cruiserweight champion David Haye took on 7ft, 316lb heavyweight king Nikolai Valuev in Nuremberg, Germany back in November 2009. But Haye’s punch-perfect display of boxing, in and out of range of his giant opponent, was enough to claim a mixed decision on away soil.