Only in the movies does Rocky slay the beast. In real life the heroic no-hoper is devoured by the monster, thereby becoming further fodder for its creation.
Such was the fate which befell Liverpool's Rocky on a cold werewolf night in the city that never sleeps.
gorged himself so lasciviously on Rocky Fielding that he is now possessed of the sustenance to be twice the fighting animal who had emerged from two wars against Gennady Golovkin
as the controversially unified middleweight champion.
Canelo plundered a super-middleweight belt to become one of the small coterie of Mexican boxers who have held world titles in three weight divisions.
Fielding was demolished by no fewer than 35 steam-hammer body blows inside three rounds. Four of those gut-wrenching punches sank him to his knees.
The last two, in the third, were more than enough for referee Ricky Gonzalez to shepherd him away to the safe harbour of his corner.
Was this a mis-match? Yes, but not fully predictable in its scale. Canelo has gained immeasurably from the two debatable decisions — the draw and a win — he was gifted against Golovkin.
As a sceptic of the Las Vegas verdicts, I now suspect that if a third fight with Golovkin does transpire then the Canelo we have just seen at demolition work in Madison Square Garden will be truly victorious third time round.
So should the Fielding match have been made?
On balance, yes, since there was only one way of knowing whether Canelo had been endowed or diminished by the Golovkin battles. As his Golden Boy promoter Oscar De La Hoya observed: 'No one else has ever risked going against Triple G's punching power in back-to-back fights.'
With Fielding's sacrificial assistance we confirmed the answer yes, because our Honest Joe Rocky was given his near-15 minutes of fame, as well as for him and his family a life-altering purse of more than a million pounds.
'I dared to go for greatness and I loved every minute on this stage,' said Fielding. 'But I ran into the best pound-for-pound fighter in the world today.'
Our Rocky took some hefty clouts to the head, too, but thankfully not enough to cloud his appreciation of Canelo (right): 'It's not just the power of the punches. It's the precision accuracy, the unseen angles, the speed of the hands, the foot movement, the balance, the defence.
'He's the complete box-fighter now. Including his defence, right down to the chin when needed. I caught him with some good shots but he just walked through them.'
Fielding added that he should have used his height — almost five inches the taller at 6ft 1in — and his reach — similarly advantageous — to keep the fight at long range. Quite simply, he couldn't.
The Garden's original Raging Bull —Jake LaMotta as portrayed by Robert De Niro on screen — would have been proud of him on Saturday night.
As were the thousands of Mexicans who helped fill this grand old arena to over-flowing, raising its roof with their Mariachi salutations to a man redeemed as their national hero after a frisson of doubt as to whether it really was contaminated meat which gave rise to a positive drugs test.
Whatever the past, Canelo now is a true force of nature.
The general secretary of the British Boxing Board of Control, Robert Smith, came hoping to oversee an historic upsetting of the odds of 1-33 on Canelo, 10-1 Fielding, but left saying: 'Canelo really is special. Not a single punch was wasted.'
Rocky responded to Canelo's opening assault with some snappy combinations, until a body shot dropped him.
Suitably encouraged in his fight strategy, Canelo went body-snatching in the second and Fielding subsided again.
Rocky began the third with a salvo to the head but Canelo swatted off those punches and then dropped him twice more with howitzers to the midriff.
History made, too. Admittedly the WBA belt of which Fielding was most forcibly relieved is the secondary in the WBA's peculiar classification of double world titles but given the manner of its winning that is only a technicality as far as Canelo's three-division world-title resume is concerned.
As a winded Rocky gasped at the end: 'This man just takes your breath away.'
Canelo will no doubt continue do just that in the T-Mobile Arenas in Las Vegas come Mexico's Cinco de Mayo patriotic celebrations in the spring, against an as yet unidentified challenger in a division yet to be resolved. Be it super-middle again or back down at middleweight.
Rocky will return to more mundane toil back home. Albeit seven figures the richer and with the sound and the fury and the memories of Madison Square Garden still ringing in his ears.