City is the new Kings of Manchester!

After a quarter of a century at the helm, after conquering Europe twice and England 12 times, an unwanted scenario beckons for the Scot. The most decorated manager in history may see his side officially second best in his adopted city.

As United's taunts rebounded on them, the City support gloried in Ferguson's misfortune. "Fergie's cracking up," came the chorus. "The noisy neighbours are getting louder, Alex" - the knighthood went unacknowledged - read a banner. Roberto Mancini was subjected to a blast of the hairdryer after Nigel de Jong's cynical challenge on Danny Welbeck. But, rather than cowering, the Italian responded in kind.

It was an argument that continued after the game. "Mancini was badgering the ref and the fourth official all game," Ferguson complained. The Italian countered sarcastically: "He doesn't talk with the referee or the fourth official. Never."

If it was petty, it was also symbolic. City have stood up to United this season, casting off the age-old inferiority complex to beat them by an aggregate score of 7-1 in the league derbies and secure a substantial lead on goal difference with two games to go. "They are in the driving seat and we are up against it," Ferguson admitted. Implausibly yet somehow predictably, Mancini insisted: "They have a slight advantage." His analysis of the situation at the summit was: "It doesn't change anything. We are there [first] but we need to win the next two games." They are against Newcastle and QPR - the reasons the Italian claims United are favourites.

Yet his side hardly played like underdogs. Vincent Kompany and Joleon Lescott were twin bastions of defiance in defence, Gareth Barry and Yaya Toure the dominant midfield axis. Gael Clichy, long troubled by Nani, triumphed against his tormentor on one wing; on the other, Pablo Zabaleta played like a man possessed.

They rose to the challenge while United shrank from it. For the first time since May 2009, they failed to record a shot on target in a Premier League game. Theirs was a timid toothlessness.

"It was a damaging result," Ferguson said. Yet his intention was damage limitation, to preserve United's three-point advantage. "For them it was important to play for a draw," Mancini argued. "They played with all the players behind the ball."

It was an exaggeration. The nine-man rearguard worked for Chelsea in the Camp Nou, but it is not a failsafe policy. In any case, this was not so much the Di Matteo masterplan as a scheme plucked from United's past, an old tactic of crowding the midfield for away games in Europe. It has only really been revived at Anfield in this league campaign, when United escaped with a draw. There was no repeat, no reprieve after conceding first.

GettyImagesVincent Kompany celebrates scoring the only goal of the game

Ferguson's tinkering backfired. The man brought in from the cold illustrated why he had languished there. Park Ji-Sung had only made two league starts in 2012 but was summoned to man-mark Toure. The powerhouse had a constant companion in the early exchanges but preferred the single life, would-be marker left trailing in his wake. A big-game player proved a major mistake: 'Three Lungs', as Park is nicknamed in his homeland, is more like 'One Lung' now, puffing like a serial smoker before being replaced.

Plan B entailed the introductions of Danny Welbeck, Ashley Young and Antonio Valencia. It was no more productive than the original approach. Indeed, City, exploiting the extra space, almost added a second goal when Toure twice shot wide, De Gea pushed Clichy's shot away and Samir Nasri tried to dribble the ball in.

Their goal came in more prosaic fashion. Kompany beat Chris Smalling to David Silva's corner. After leading by example all season, he may be a fitting scorer for the biggest derby in the fixture's 118-year history. As he is married to a Mancunian, he is, in some respects, the closest to a local in the City side. Not that a surprise visitor to City's press conference room agreed. "Vive la Belgium," Liam Gallagher said. The former Oasis singer was crowing on a night when City were feeling supersonic and United had plenty of reasons to look back in anger.

MAN OF THE MATCH: Pablo Zabaleta. If much of the build-up focused on Carlos Tevez and Sergio Aguero, the unheralded Argentine flourished. At times Zabaleta was a one-man right flank, appearing in either box with considerable effect. He also kept Ryan Giggs quiet to reinforce his reputation for delivering on the major stage.

MANCHESTER CITY VERDICT: The more positive side were the deserving winners, with Ferguson accepting he could not complain about the result. Toure showed why he has been the Premier League's outstanding central midfielder this season and Kompany why he has been the finest centre-back. Mancini's regret was that they did not score the second goal that would have improved a goal difference already eight superior to United's.

MANCHESTER UNITED VERDICT: It was another chastening derby that leaves them reliant upon others for favours, even if Mancini - again - said their last two games, against Swansea and Sunderland, are "easy". If the initial tactic was unsuccessful, it was understandable. But it was more damning that United did not test Hart thereafter. Park was utterly ineffective while Paul Scholes and Ryan Giggs, long the derby talismans, could not repeat past heroics.

DIEGO WHO? The game was graced by the presence of Diego Maradona, otherwise known as Aguero's father-in-law, but the man brought onto the pitch at half-time was Shaun Goater. There is something quintessentially City about that, something endearing in the applause granted to a reminder of their days in League One. That was in 1999, when they were third tier and United were European champions.