After 2,062 games, 48 trophies and 37 years, the scope for novelty is almost non-existent. Everything comes coated in context, the extremes of emotion rarely approached. Yet occasionally something so remarkable, so ridiculous, happens that even the doyen of managers has known nothing like it. "It's the worst result in my history, ever," Sir Alex Ferguson said. "Even as a player I don't think I ever lost 6-1. I can't believe the scoreline. It was our worst ever day."
Statistically, it was Manchester United's poorest at home to Manchester City since 1926, defensively their nastiest at Old Trafford in the league since 1930. Not since the Great Depression had they let in six. Now a new sense of despondency has taken hold. Given sleepless nights by City after a 5-1 derby defeat at Maine Road in 1989, Ferguson may return to the ranks of the insomniacs. For that, among other things, he can thank another who cannot get to his bed. Whatever the burns damage to his fixtures and fittings, however, Mario Balotelli has scarred United rather more.
Footballers are often accused of being out of touch and few appear as distant from normality as Balotelli but, for once, he managed to express the thoughts of thousands. "Why always me?" read the T-shirt he unveiled to accompany a typically stony-faced celebration to the first of his double. Why indeed?
The answer to Balotelli's question could require a book, not to mention an in-depth psychological profile. A shorter response entails mention of the Italian's blend of huge talent and questionable temperament. But as City recorded a result with potentially colossal consequences, it was always Balotelli. Scorer of the first and second goals, the man responsible for Jonny Evans' dismissal and the scourge of United. With six goals in five games he is, much like his bathroom in the early hours of Saturday morning, on fire. With six goals in 90 memorable minutes, City set Old Trafford ablaze as United self-combusted.
"I love him like a guy," Roberto Mancini said, discussing Balotelli more in terms of budding bromance than disciplinarian manager and errant charge. His latest escapades met with a grin. "He is Mario. He is crazy. I know he sleeps in a hotel now, but I don't know what has happened," Mancini added. "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."
City's twisted firestarter has long had an incendiary impact; this time the fireworks he detonated lit up the title race. The collateral damage may only be evident in May but this was a seismic win, with a sensational scoreline to suggest the balance of power in Manchester may finally be swinging towards the blue half. Not that Mancini agreed, admittedly. "I think United is still one yard above us," he insisted, ignoring the evidence of the previous 90 minutes.
It was numerically superior but otherwise comparable to Liverpool's 4-1 triumph in March 2009. That threatened to dethrone United as champions; this could enable City to accomplish it. Their task is to overcome years of inferiority, in both the city and the country. This was an auspicious start. After 19 successive home league wins and 37 unbeaten games over 18 months, United's fortress was stormed.
For once, Old Trafford was City's Theatre of Dreams, the role of protagonist going to a man who often supplies comic villainy. For the 70 minutes until Mancini removed him, it was always Balotelli, but not only Balotelli. The supporting cast delivered award-winning performances themselves. James Milner, so unproductive so often in a City shirt, has found a rich vein of form. He was involved in the first three goals, supplying the final pass for Balotelli's brace.
David Silva was David Silva, threading delicate, delightful passes through with understated excellence, illustrating his virtuosity with a glorious hooked ball for Edin Dzeko's second and getting on the scoresheet himself. The Bosnian, limited to 20 minutes, scored two and could have had two more as City ran riot. None was more rampant than Micah Richards, who delivered a dynamic display at right-back. He provided a power surge every time he broke clear on the right flank.
"In the end they are only three points," Mancini said. "Not six." But there were six goals. It was Balotelli first, guiding a shot into the far corner, after Silva and Milner played delightful passes. The same trio combined for the second goal, a tap in for the Italian. By then, he had bade farewell to Evans, who achieved an unwanted hat-trick by being culpable for the opener, spurning a sitter and then tugging back the City striker when the last man. "That was the killer blow," Ferguson said, accepting it was the correct decision.
The second goal opened the metaphorical floodgates. United started staging a convincing impression of Arsenal's defending at Old Trafford in August, lacking organisation and communication. Richards' low cross was converted by Sergio Aguero. Then, following a brilliant finish from Darren Fletcher, City responded with three goals in four minutes. Dzeko touched in a cutback from Joleon Lescott and supplied the finish to accompany Silva's exquisite pass. Sandwiched by the Bosnian's brace, the Spaniard placed a shot through David de Gea's legs.
"The manner of the defeat is the bad one," Ferguson said, noting a swing of ten in the goal difference. "There's a lot of embarrassment in the dressing room and rightly so." The ever careful Mancini insisted that "four or five teams" can win the title, the vanquished United among them. Yet his wild card is threatening to be his trump card.
Almost two decades ago, as United ended a 26-year wait for a league title, the catalyst was another master of the unpredictable, Eric Cantona. City's wait has been still longer and, compared to the Frenchman's philosophical musings, his eccentricities can make seem a rebel without a clue. Yet as he propelled them into a five-point lead with a six-goal win, City could savour the beautiful madness of Balotelli.
MAN OF THE MATCH: Mario Balotelli. There are so many candidates, all in sky blue, but the decisive moments all revolved around Balotelli. It is too soon to suggest the 21-year-old is maturing, but he is making an impact regularly now.
MANCHESTER UNITED VERDICT: A chastening, shocking afternoon. The champions have rarely been secure at the back this season, but they were awful in the second half. Ferguson attributed the late concessions to their attempts to get back into the game but his side lacked shape and structure at the back with ten men. With 11, Evans was error-prone again, posing the question of why he was selected to start.
MANCHESTER CITY VERDICT: Brilliant. Mancini's decision-making was terrific, starting with Milner, Richards and Balotelli when many might not have done, and his players executed the game-plan superbly. In the last couple of years, only Barcelona demolished United as superbly and as stylishly as City did. It was a performance of two halves, solid and efficient when against 11 men and dramatically dominant against ten. The hunger they showed for goal after goal was indicative of a change in their mentality this season.