Essien's return to the side following his cruciate ligament injury in August has been a major boost for the Londoners who were also able to start with Ricardo Carvalho and Deco.
In the clash of the two richest clubs in the world, it was Roman Abramovich's outfit that looked best equipped to mount a tilt for titles.
Chelsea dominated from the off and Frank Lampard had the ball in the back of the net within a minute but was adjudged to be offside.
The Chelsea breakthrough came on 18 minutes when Lampard sent in a clever free-kick and Essien popped up, unmarked just inside the City penalty area, to clip an exquisite right-footed half-volley over the stranded Shay Given.
City almost equalised five minutes later when Stephen Ireland fed the ball to Felipe Caicedo, His first time touch and turn ended with a low left-footed drive that just went wide of Petr Cech's left upright.
Chelsea looked to have won a stonewall penalty on 32 minutes when Nedum Onuoha appeared to tug Nicolas Anelka's shirt twice as the frontman ripped into the City penalty area, but referee Mike Riley waved play on.
Chelsea almost nabbed a second goal nine minutes before the break when Michael Ballack won possession before passing to Lampard who fed Didier Drogba.
The Ivory Coast international then back-heeled the ball into the path of the onrushing Ballack, who stretched to get to it but failed to guide his effort towards goal under pressure from Richard Dunne.
Deco's return lasted just 40 minutes when he appeared to suffer a recurrence of his hamstring injury before being replaced by Juliano Belletti.
A fine counter-attacking move on 51 minutes saw Lampard give the ball to Jose Bosingwa who quickly passed it on to Drogba. He took one touch before rifling the ball on target only to see Given make a smart diving save.
City boss Mark Hughes had seen enough and replaced Caicedo with Ched Evans.
Gradually City increased their share of possession and forced several corners although none troubled the Chelsea goal.
It was Chelsea who could have scored their second when another quick counter-attack on 63 minutes saw Belletti start the move and end it with a 20-yard left footed daisy-cutter which beat Given but not his left post and the ball bounced clear.
Dunne cleared Florent Malouda's effort off the line with six minutes left as Chelsea professionally played the clock down before securing another vital three points.