Yaya Toure and Joe Hart were the heroes at either end of the pitch for City, the former scoring the game’s first goal – a real beauty – and the latter preceding the Ivorian’s clinical finish with a fine penalty save from Frank Lampard.
A Carlos Tevez stunner from the edge of the box five minutes from time added gloss and some perspective to a superb three point haul.
Given United’s continued winning streak and the proximity and ambition of North London heavyweights Arsenal and Spurs, a single point from the this contest was never going to be nectar to either of these sides.
Attacking intent was frothing and fermenting from the off - even if the whistle often thwarted the home side.
The reigning English and European champions served up a Cup tie draped in the EPL flag!
It was City who made most of the running creating half a dozen openings in the first half but unable to make any of them count.
Chelsea on the other hand, despite a welter of free kicks awarded in their favour, produced little in front of goal.
Mancini’s men came into the contest with just two points from the last nine and with the added irritation of United heading for the horizon. The players also still had the criticisms of the manager ringing in their ears and it was only slightly mollified by the crushing of Leeds in the FA Cup.
After seeing their movement and precision undo Leeds 4-0 so comprehensively in the previous home game one might have expected Mancini to stick with his all-Argentine strike force of Sergio Aguero and Tevez. But the latter dropped to the bench alongside Samir Nasri and Edin Dzeko.
Instead, the home side mirrored their visitors and added numbers in midfield. Jack Rodwell returned to start a first Premier League game since the start of September and Yaya Toure and David Silva were detailed to provide a rapid response force for Aguero.
After last season’s twin glories it has not been an easy season for either of these sides but despite Champions League disappointment they both remain big beasts in the domestic jungle.
It’s easy to see why Premier League sides find it hard to contain them. There was a precision of passing, cleverness and subtlety of movement and an innate willingness to work without the ball that suffused both sets of star names.
With the mercurial talents of Silva, Juan Mata and Edin Hazard all on the pitch at the same time and supported by the power of industry of Yaya Toure and Frank Lampard this game had every hallmark of a cracker.
But it fizzed and sizzled only sporadically as both teams became anxious in their desperation to collect the three points and secure the position of best of the rest before setting off in pursuit of the leaders.
City enjoyed the better openings. A first minute Yaya shot was saved by Cech low down and then the Chelsea batted away a 15th minute free header from Matija Nastasic who arrived quickly on to the corner from Silva but produced neither enough direction or power in his header.
Rodwell was later off target with a header but this was an impressive effort from the young midfielder who, with foot and head, brought two saves from Cech as the half closed.
With James Milner driving them on from the middle it seemed only a matter of time before City scored but first they had to survive a penalty when Hart fouled Ba. England’s number one can count himself unlucky but pulled out a stunning save low to his right.
He was rewarded in the 63rd minute when Yaya kept his head and curled a shot around Cahill and beyond Cech to open the scoring. Tevez condemned Chelsea to a fourth straight defeat at the Etihad and kept the title defence alive.
