Fifty years ago next week the world of sport was to change for ever. A lippy young teenager from Louisville, Kentucky named Cassius Marcellus Clay arrived in Rome as light-heavyweight representative in the United States Olympic boxing team of 1960.

Even before he pulled on his headguard and gloves he was prophetically proclaiming: "I am The Greatest".

Within a couple of weeks he was the Olympic champion, giving us a taste of the mouthy magic that was to come just under four years later at 22 when, as he had threatened, he "shook up the world" by psychologically disheartening and physically dismantling the bullying ogre that was Charles ‘Sonny Liston’ to became the heavyweight champion of the world as well as the word.

As an Olympian the young Clay was already exhibiting some of the nimble fleet-footedness and sleight-of-fist that was to become his inimitable trademark. In his semi-final he outpointed the 30-year-old Aussie Tony Madigan, who was boxing in his third Olympics and during a stay in Britain has become the 1954 ABA middleweight champion. The final saw another decisive victory, a 5-0 points shutout of the seasoned Polish southpaw, 26-year-old Zbigniew Pietrzykowski who, in the previous Olympics in Melbourne had lost in the semi-finals to the Hungarian Laszlo Papp, arguably the greatest-ever Olympic boxer.

Clay used the Olympics to launch himself towards the global celebrity he was to become as Muhammad Ali.

Alas, I never saw him win the gold medal he later claimed he had thrown into the Ohio River when he was refused service in a diner because of his colour (a story he later admitted was apocryphal – he simply lost it).

My first Games came four years later in 1964 when my claim to fame,  was that I actually put the Olympic heavyweight champion  of that year on his back. It happened when I was strolling through the Olympic Village in Tokyo (in those security-lax  days journalists had virtually unfettered access). Hurtling around corner on  a bike came a young black guy, his enormous thighs pushing down furiously on the pedals. He  swerved to avoid me, and crashed to the ground. "Sorry man," gasped Joe Frazier as he picked himself up. "You ok?" I was, and fortunately so was he.

The next time I saw "Smokin" Joe on the deck ws in Kingston, Jamaica in 1973, where he was sent five times in two rounds by a successor as Olympic and world heavyweight champion, one George Foreman.

As Olympic boxing champions go, Clay, Frazier and Foreman were among the finest, along with Lennox Lewis. But the one who impressed me most was the Cuban, Teofilo Stevenson (pictured), whom I dubbed Castro’s right hand man because of his phenomenal punching power. The first of his three gold medals was acquired in Munich in 1972. Just before those infamous Games, my good friend Colin Hart of The Sun and I happened to be talking to Ali’s trainer, Angelo Dundee, and mentioned that we got to Munich we planned to interview a heavyweight boxer Named Duane Bobick, who was being hailed as America’s next white hope. "Don’t bother," said Angie. "Go and see a Cuban kid named Stevenson. He’s sensational. He’ll knock out Bobick." He did, too.

As a true disciple of Casto’s communisn, Stevenson rejected all offers to turn pro -what an fight he and Ali would have been. Though as always, my money would have been on the great Muhammad.

Well, not quite always. I confess when  the then Clay fought Liston for the first tine at Miami Beach in February 1964 I did not give him a prayer. Liston was the most terrifying individual I have ever encountered in boxing. There was nothing sunny about Sonny. A sullen, brooding hulk who had served time for armed robbery and who had clubbed most opponents senseless, including another great Olympic champion, Floyd Patterson. I thought Liston would annihilate young Cassius and I was not alone.

The first fight took place three months after the assassination of John F. Kennedy when the whole of America was in turmoil. Liston was a fighter run by racketeers, his manager having close association with two of the mafia’s most infamous hit men, Frankie Carbo and ‘Blinky’ Palermo who, at the time, had their claws into boxing and had been known to profit from betting coups on fights.  Clay, the loudmouthed  braggart was not to America’s liking either. It was a fight with no hero but two villains.

The late Harold Conrad, the fight publicist, had said: "Liston scared the shit out of Patterson just by looking at him and here comes this big-mouth kid.  He [Liston] didn’t train at all for that fight. He worked out a little and went to the gym. He would hang out at a beauty parlour, banging on some of the chicks. I’d tell him, ‘This kid is big and strong, he’s fast and he can hit.’  Sonny would just answer, ‘Ah you’re kidding.  I’ll scare the shit out of that nigger faggot … I’ll put the eye on him.’"

But as it happened, it was Clay who put the eye on Liston. Learning that Sonny, who claimed to be 32, but was probably nudging 40, had a phobia about madness, he put on an act at the weigh-in, foaming at the mouth and screaming like a dervish. It seemed to scare Liston witless and by the end of the sixth round of a baffling fight he quit his stool, bemused and battered, saying he had a shoulder injury.

The crowd screamed "Fix" but I have always believed Ali, as he was to become after the fight, psyched him out of it, and did so again  the even more bizarre return at Lewiston, Maine, when  Liston fell in the first, caught of balance by the so-called ‘phantom punch.‘

Again they said it was bent. But I believe Liston, knowing he would be cut to pieces by the arrogant youngster hovering over him and yelling, "Get up you bum, get up you bum and fight!" simply bottled it, fearing he was again going to be humiliated and probably sliced to pieces. In the months following their first fight Ali had grown up while Liston he had simply grown old and like all bullies, he was a coward at heart.

Their two-fight saga is is brilliantly recaptured by the boxing historian Bob Mee in the first book to dissect and debate two of the most controversial heavyweight title fights in history*.

Was Liston told to take a dive by his mob paymasters? I think not – after all, why would the Mafia want to surrender the richest prize in sport to the Muslims?

Seven years later Liston was found dead in mysterious circumstances at his Las Vegas home. The official autopsy said natural causes despite syringe marks on his body and heroin in his blood. And needles had always been another of Liston’s phobias. Whether he was deliberately injected with heroin by gangsters as a belated reprisal for his abject performances against Clay-Ali we will never know

As for Ali, he has always maintained both fights were on the level and I think so too.

He rarely remembered names, but he recognised faces especially those who had been warmly supportive of him over the years, particularly the British writers with whom he had a genuine affinity. Now the horrendous effects of too many punches and Parkinson’s Syndrome have wracked his body though not his mind.

The lips that once spoke volumes are sadly silenced now. The last time we spoke was at ringside in Las Vegas over a decade ago.  I felt a hand on my shoulder and turned to see the shuffling, shaking figure of Muhammad. He bent and whispered in my ear "It ain’t the same any more, is it?"

"No champ," I replied. "It ain’t."

Sadly, it never will be again.

Alan Hubbard is an award-winning sports columnist for The Independent on Sunday, and a former sports editor of The Observer. He has covered 11 summer Olympics and scores of world title fights from Atlanta to Zaire.

* Liston & Ali – The Ugly Bear and the Boy Who Would Be King by Bob Mee  is published by Mainstream at £10.99