May 7, 2016; T-Mobile Arena, Las Vegas

HINDSIGHT makes this matchup even more ridiculous than it was at the time. Out of the ring for a year and eager for a super-fight, Khan jumped two divisions to take on the fearsome Alvarez. The pole-vault to middleweight – albeit at a catchweight of 155lbs – effectively finished Khan as an elite fighter. Alvarez boiled down to make weight, Khan inflated his body to get somewhere near it and on the scales, outside on a windy and drizzly day in Las Vegas, the difference in the physiques was stark. Come fight night, the contrast even greater. The brave Briton started well, however. Yet the flicking shots he threw were always hampered by the need to stay out of trouble. Alvarez merely waited for his chance and when it came, towards the end of round six, he launched a now famous overhand right that put Khan to sleep on impact.

DID YOU KNOW? The post-fight press conference was delayed by two hours as Alvarez took a drug test and Khan was rushed to hospital. Midway through, promoter Oscar De La Hoya received a call from the hospitalised Amir who reported he was okay. He didn’t fight again for two years.

WATCH OUT FOR: Alvarez ignoring any punches coming his way while plotting the finish – the KO punch was a long time coming and carefully calculated.

Canelo vs Khan boxing
Tom Hogan/Golden Boy Promotions

May 11, 1981; Madison Square Garden, New York

NORTON, after a decade exchanging fearsome shots with some of the best fighters in history, was unquestionably approaching the end at the age of 37 (though then listed as 35). But the number 10-ranked veteran had experience on his side and – in his mind – a knack for exposing young pretenders. He took on Cooney four years to the day after he had knocked out the 38-0 Duane Bobick in 58 seconds inside the same Madison Square Garden.

This bout wouldn’t even last that long. Cooney had only 86 professional rounds under his belt (compared to Norton’s 313) but needed just 54 seconds to score one of the most gruesome KOs in heavyweight history.

Stricken in his own corner after taking two left hooks, Norton was walloped senseless as he dribbled to the floor. The 24-year-old showed no mercy, hurling power-shots at his man until referee Tony Perez eventually jumped in.

DID YOU KNOW? Marvis Frazier moved to 4-0 on the undercard as he became the first man to stop  a still ambitious Steve Zouski. Zouski, then 21-1, later became popular fodder for several big names including Mike Tyson, George Foreman and Tommy Morrison.

WATCH OUT FOR: You can find the full HBO broadcast which includes some interesting pre-fight interviews with both fighters and their respective teams.

May 13, 1989; Great Western Forum, Inglewood

MAYWEATHER was being dubbed “The Mexican Assassin” after beating six Mexicans in the build-up to this rematch with the great Julio Cesar Chavez. Mayweather brushed it off as marketing spiel and preferred to stick with his self-anointed nickname, “The Black Mamba”. The contest did need some selling. Chavez had ripped through Mayweather in two rounds in their first bout in 1985 and almost all predicted more of the same for the sequel. Roger’s topsy-turvy career was at its highest peak, however: He had won 14 of 16 since that shellacking and picked up the WBC super-lightweight crown along the way.

Chavez, then an incredible 62-0, was aiming for another title in a third weight class after ruling at super-feather and lightweight. Mayweather fared better this time, stinging the Mexican on occasion with his signature right hand but invariably taking punishment in return. At the end of the 10th round, Mayweather’s corner pulled out their exhausted charge.

DID YOU KNOW? Sugar Ray Leonard pulled out of his HBO commentary duties because he was preparing for his June 1989 rematch with Thomas Hearns.

WATCH OUT FOR: A fascinating pre-fight film that outlines the reasons for Roger’s journey from his Grand Rapids, Michigan birthplace to his adopted hometown of Las Vegas, where of course the whole Mayweather clan would follow him to.

May 11, 1991; John O’Donnell Stadium, Davenport

NUNN was fed up of being panned by the fight media and sick to death of James Toney. The IBF middleweight champion rose to prominence with a series of exhilarating performances but drew criticism from the press for his last three (against Iran Barkley, Marlon Starling and Donald Curry).

With the cocksure Toney getting under his skin in the runup to battle, Nunn – perhaps more so than at any other point in his career – was determined to put on a show in front of his hometown fans.

And through the opening six, Nunn boxed the best rounds of his life. He dominated before the exertion, and Toney’s patient pressure, started to take its toll. Toney sensed his opponent tiring – “I can hear him breathing like a freight train,” he told his trainer Bill Miller between rounds – before finishing Nunn in a violent 11th.

DID YOU KNOW? Nunn’s trainer Angelo Dundee, sensing danger from Toney’s right hand, tells Nunn to move to his right before the fateful 11th. Toney triggers the finish by decking Nunn – who was following instruction and moving to his right – with a huge left hand.

WATCH OUT FOR: That finish. Miles behind on the cards, Toney rendered them useless as Nunn was savagely taken out.

May 7, 2005; Mandalay Bay, Las Vegas, NV

IT’S clear as the two fighters make their way to the ring past empty seats that the event was far from a sell-out. What you’d give for a time machine and enough dollars in your pocket to get a ticket. Because what followed between WBO lightweight champion Corrales and Mexico’s WBC boss Castillo was a humdinger of the ages. The Las Vegas-based Californian knew it was going to be special at the open workouts two days before the fight he hugged Castillo and told him: “We’re going to make some history.” You don’t need us to tell you what happened. But we will tell you, after watching this for the umpteenth time, it remains as scintillating as always. That 10th round – with the knockdowns and the gumshield controversy and the brutal turnaround – is as dramatic as anything you will ever see.

DID YOU KNOW? Corrales wasn’t aware in the aftermath or during the fight it was a classic. It was only as he walked away from the arena it dawned on him.

WATCH OUT FOR: Corrales’ trainer Joe Goossen, as he replaces his fighter’s mouthpiece for the second time after the second knockdown in the 10th, saying calmly, “You gotta f**king get inside on him now.”