MANCHESTER // Some chants can seem a delightful fantasy for years but be rendered irrelevant within seconds.
Enjoying a cathartic, historic revenge after years of taunting from the overbearing superpower from across town, the Manchester City supporters, transformed into deliriously noisy neighbours, launched into a chorus of "5-1 in your cup final".
And then, before they could contemplate an encore, it was 6-1, United shipping a sixth goal at Old Trafford in a league game for the first time since 1930. It was that sort of afternoon for City, a credibility-defying day that will assume a prominent place in the club's folklore.
Should they realise their ambitions, posterity's verdict will be that this was the match the balance of power in Manchester shifted from red to blue. Even if they don't, there was so much to savour that it is hard to know where to begin.
With David Silva, perhaps?
The unobtrusive instigator of all that is good about City furthered his claim to be the Premier League's outstanding player, guiding passes through gaps with masterly precision.
Or James Milner, maybe?
A man who appeared overpriced and was underwhelming in his first year in Manchester has come of age.
He played a pivotal part in each of City's first three goals.
Possibly Micah Richards?
City's longest-serving player has been at the club since the age of 13, a decade in which United have dominated ruthlessly.
He powered along the right flank, supplying Sergio Aguero for the third goal.
But, as ever, it is hard to ignore Mario Balotelli.
His weekend went as follows: Saturday - set off fireworks in his bathroom, resulting in much of his house being ablaze; Sunday - star in City's biggest derby win at Old Trafford for 85 years. As the T-shirt he revealed after opening the scoring read: "Why always me?"
It is a question City have pondered many times over the past year.
Having persisted with this enfant terrible when others would not, Roberto Mancini, the City manager, could afford to be indulgent.
"I know he sleeps in a hotel now, but I don't know what has happened," he said.
"He is Mario. He is crazy. If we want to talk about Mario as a football player, I think we can put him in the first five players in the world."
Heady praise but, on this evidence, justified. He has six goals in five games, two of them the crucial strikes in what Sir Alex Ferguson, the United manager, deemed "our worst ever day".
Nothing separated the sides, however, until, with perfect precision, Balotelli placed the first goal in the far corner of the net.
The triangle of Silva, Milner and the Italian, combined again for the second, the Englishman's low centre converted by Balotelli.
Before then, United's inability to handle Balotelli was epitomised when Jonny Evans tugged him back and was sent off. "The killer blow," said Ferguson.
A one-man advantage became a five-goal lead. The barnstorming Richards supplied Aguero for his 10th City goal.
Then, after a glorious strike by United's Darren Fletcher, City struck three times in four minutes, the substitute Edin Dzeko with a brace to sandwich Silva's finish.
Yet the emblematic moment of the Spaniard's afternoon was the wonderful, hooked pass to send the Bosnian through for the final goal. His was an immortal display of artistry.
"I can't believe the score line," Ferguson said. "It's the worst result in my history, ever."
By the same standards, it may be City's finest.
Only one man remained calm. "We don't take six points," said Mancini. "They are three points. I think United are still one yard above us."
Try telling that to the travelling supporters revelling in Ferguson's unprecedented humiliation. The Blue Moon has rarely been higher.