LAS VEGAS: Andre Berto will pull off one of the biggest shocks in boxing history if he defeats unbeaten welterweight world champion Floyd Mayweather on Saturday in Las Vegas.

Here we look at five victories that rattled the boxing world:

George Foreman vs Michael Moorer (November 5, 1994)

George Foreman was 45 and out of shape. Some said he shouldn't even be in the ring. Michael Moorer was 19 years his junior and expected to send the former heavyweight champion into permanent retirement.

Foreman was trailing all three judges' scorecards in Las Vegas when out of nowhere he rolled back the years to flatten the previously unbeaten Moore in the 10th round and become the oldest heavyweight champion in history, regaining the title he lost two decades earlier.

He later made light of his ill-fitting shorts, telling reporters: “These are the shorts that I fought in when I was heavyweight champion of the world. They are short and make you look a little chubby, but I fought Muhammad Ali in these shorts.”

James ‘Buster’ Douglas vs Mike Tyson (February 11, 1990)

“Iron” Mike Tyson was the baddest man on the planet. A heavyweight who was also devastatingly quick. He was undefeated in 37 fights, 33 of them knockout, and held three belts.

In contrast, James “Buster” Douglas was a journeyman carrying too much weight and not enough talent. A rank outsider at 42-1 against, his mother died in the lead-up to the fight, disrupting his training camp.

But against all the odds, Douglas dominated at the Tokyo Dome almost from the first bell and knocked out the feared Tyson in the 10th with a brutal flurry of punches that left Tyson scrambling around on all fours on the canvas.

“It was unbelievable, but this is something that can happen. It is one of the biggest upsets in sports history,” promoter Don King recalled later.

Muhammad Ali vs George Foreman (October 30, 1974)

Undefeated heavyweight world champion George Foreman was widely expected to batter Muhammad Ali in the “Rumble in the Jungle” in a baking Kinshasa, in then Zaire, in the most famous bouts of all time.

Ali was past it at 32, they said, and feared for his health; they were wrong. The former champion's now famous “rope a dope” strategy of staying on the ropes, gloves up, saw Foreman punch out his energy.

Ali pounced on his exhausted foe with a series of shuddering blows that sent Foreman crashing down for an eighth-round knockout, the first defeat of his career. “I wanted to make him shoot his best shots,” said Ali later.

Cassius Clay vs Sonny Liston (February 25, 1964)

Cassius Clay — who later changed his name to Muhammad Ali — was a 22-year-old upstart heavyweight with plenty of talent but too much to say. He was also going into the fight having been floored by Henry Cooper.

Sonny Liston was the hot favorite, having forged a fearsome reputation built on two first-round knock-outs of Floyd Patterson. But all that stood for nothing in Miami.

Liston was on top at first but Clay busted his opponent's eye in the third and the man who would go on to become known as the best ever was crowned heavyweight champion when Liston retired on his stool at the end of the sixth.

A triumphant Clay declared to the world: “I am the greatest!”

Sugar Ray Robinson vs Randy Turpin (July 10, 1951)

Ring legend Sugar Ray Robinson — one of the best boxers ever — faced the relatively unknown Randolph Turpin in London on a streak of 91 fights unbeaten over a nine-year period.

Turpin was a respected fighter but was thought to have nowhere near the class to trouble his more illustrious opponent, never mind defeat him.

All that counted for nothing as the pair went toe-to-toe for the world middleweight title, after which Turpin was awarded the shock — but deserved — winner.

Critics said Robinson had not taken Turpin seriously enough and failed to train properly.

The American accused the Briton — who appeared to revel as the underdog — of adopting a “ruffian style” in front of a raucous home crowd.