John H. Stracey silenced 40,000 locals packed into a Mexico City bullring by beating their hero Jose Napoles for his WBC world welterweight title 40 years ago today.
The upset remains one of the best world title wins by a British boxer on foreign soil after the Londoner recovered from an early knockdown to box his way to a sixth round victory and leave Napoles with cuts and a swollen face.
Napoles was the world welterweight No.1 after being world-title holder on and off for the previous six years.
And the champion, who was born in Cuba but left in 1961 when professional boxing was about to be made illegal, was heavily fancied to retain his titles in his adopted homeland.
But, at 35, he was there for the taking and Stracey fought the perfect fight.
Stracey had boxed in Mexico seven years earlier at the Olympics and his prior knowledge of the country meant he arrived a month before the fight to adjust to the altitude. The East Ender was not intimidated by thousands calling for his blood and, what's more, he had a plan.
However, getting floored in the first round was not part of it. Stracey got up from being dropped by a left hook and from then on put his jab to good use.
Stracey had sparred with Napoles three years earlier when the Mexican idol had visited London for a title defence. Stracey never forgot how the jab worked for him when he sparred with Napoles and in the third round it was the Mexican resident who touched down after being caught by a left.
Stracey continued with his steady beating of the aging champion, who gradually came undone. In the sixth round, with Napoles' left eye badly swollen and cut, the fight was stopped as Stracey unloaded on the ropes.
"It was my proudest moment. I had 51 fights, won 45, lost five and drew one. But once you have won a world title, it never gets better," said Stracey.
Along with Ken Buchanan's victory over Ismael Laguna in Puerto Rico in 1970, Stracey's upset is regarded as one of the best world title wins by a British boxer overseas. It has perhaps only been bettered by south Londoner Lloyd Honeyghan's upset win over undisputed world welterweight champion Donald Curry in 1986.
It was to be the last fight of Napoles' career and Stracey would make only one successful defence before losing the belt by a 12th-round stoppage to Carlos Palomino six months later. Today, Stracey is 65 and an after dinner speaker.
Nick Parkinson is the author of 'Boxing On This Day'