A goal in each half from Edin Dzeko and late third from Yaya Toure settled the 167th Manchester derby that the Blues dominated from the first minute onwards to record a Premier League double over their old rivals - and break several club records in the process.
With so much at stake and the Blues eating into the first of their three games in hand over leaders Chelsea, Manuel Pellegrini opted for a starting XI with pace and plenty of attacking options.
Jesus Navas and Gael Clichy were recalled to patrol the flanks while skipper Vincent Kompany and Edin Dzeko returned to the team after a suspension for the former and illness to the latter.
Rarely – if ever – had the Blues gone to Old Trafford in the Premier League era and begun the game as favourites, but such had United’s indifferent form been throughout this season that the defending champions knew that they had to significantly up their game if they were to stop their cross-city neighbours recording a second league double in three years.
Despite a 2-0 win at West Ham at the weekend, David Moyes also made four changes to his side as he bolstered his midfield in a bid to stifle City’s creative forces.
But the United boss must have been horrified by the way the Blues cut through his defence in the first minute to eventually take the lead.
First David Silva burst through on goal and was about to pull the trigger when Rafael slid in with a last-ditch tackle, but the ball fell to Samir Nasri who then hit the post with the rebound falling to Dzeko who scored from a yard out with a shot into the roof of the net.
There was just 43 seconds on the clock when the Bosnian scored – missing George Best’s record set in 1968 for the fastest derby goal by just five seconds – but setting a new City record in this fixture while also recording the quickest away goal ever at Old Trafford.
It was the perfect start and the only puzzling thing in the minutes that followed was the Blues didn’t double or ever treble their lead.
Silva went close on eight minutes and United were clinging on as City pressed high, forcing numerous errors but failing to capitalize on the chances created as a result.
One such passage of play on 18 minutes saw Yaya Toure pick up a poor David De Gea clearance and volleythe ball to the feet of Silva who played in Dzeko but De Gea stooped low to stop the City striker scoring again.
Thereafter, the Blues began to needlessly give possession away and allow United back into the game, though Joe Hart was rarely troubled in truth and the superb Kompany and Martin Demichelis were on hand to repel any threat through the middle.
Marouane Fellaini was fortunate to only receive a yellow card for an elbow in Pablo Zabaleta’s face as the half wore on, with the hosts’ only real encouragement coming from City occasionally mis-placing passes in an otherwise dominant opening period for Pellegrini’s side.
Just seven minutes after the break, Fernandinho somehow headed over from a Vincent Kompany flicked-on corner, but the Blues needed only another four minutes to finally increase their lead – and richly deserved it was, too.
City had looked dangerous from corners all evening and when Nasri whipped another one in on 56 minutes it fell perfectly for Dzeko whose cushioned volley flew past De Gea to send the Blue army wild.
It was the Bosnian Diamond’s 20th of the campaign – the fourth City player to reach that milestone in this goal-laden campaign - and it gave the Blues some much-needed breathing space.
Nasri and Navas made way for Javi Garcia and James Milner as the Blues’ tightened their grip but United showed they could still find a way back into the game if they were given the space and time as Welbeck’s clever back-heel proved – fortunately Hart was equal to it beating the ball away from close range.
But it was City who had the last word as Yaya Toure orchestrated a move that ended with the Ivorian cutting inside one challenge before drilling the ball past De Gea to complete a comprehensive victory.
The clean sheet recorded by Hart was also City’s fifth Premier League shut-out in succession - another new club record for the Blues who move within three points of leaders Chelsea – and still with two games in hand.
