The 32.5 million pound man paid off the first instalment of his British record price-tag by putting Mark Hughes' men ahead with a superb 13th-minute free-kick.
But it was downhill all the way after that as Chelsea scored three times without reply, through Ricardo Carvalho, Frank Lampard and Nicolas Anelka to register a seventh straight win over City even though England captain John Terry was sent off for a professional foul.
It was a reality check Hughes did not need, although it should ensure expectations are lowered - until January's transfer window opens - and in Robinho City have a talent to savour.
Given the amazing events of the last fortnight at what has now been dubbed 'Middle Eastlands' by the City support, it was perhaps no surprise Robinho should make the perfect start.
His pricetag ensures every move he makes will get monitored and a warm embrace with Luiz Felipe Scolari after the traditional pre-match handshakes did little to foster a feeling he has ended up where he wanted to be.
But any doubts over his commitment were swept away by the 24-year-old's reaction to a goal that could be a point historians will remember as the moment City's revolution began.
Carvalho was unhappy at the free-kick in the first place as Jo went down under minimal contact and Petr Cech was clearly agitated at the way his wall failed to take shape as he requested.
It just added to the theatre as Robinho ushered away all his team-mates, before reintroducing Vincent Kompany as a token presence. He then took aim and calmly stroked the ball via a deflction into the corner.
There was nothing too elaborate about his reaction, just a gleeful run towards the halfway line, thumb in mouth as South Americans do, before being mobbed by ecstatic team-mates.
With Shaun Wright-Phillips on his home debut keeping the visitor's defence on their toes with some mazy runs, all seemed set for an evening of celebration.
Unfortunately for the hosts, their lead lasted just three minutes as John Terry leapt for Frank Lampard's corner, saw his header strike Joe Cole and the rebound falling invitingly for Carvalho, who promptly lashed it into the roof of Joe Hart's net.
It was the start of a sobering period for City, which was outplayed for long stretches, with Robinho becoming largely anonymous.
Florent Malouda saw his cushioned header bounce back off the bar, then Nicolas Anelka wasted an excellent opportunity from Pablo Zabaleta's poor clearance as Deco's influence started to spread.
City was restricted to rare sights of goal, although Jo could easily have profited from one as his curling shot flew over after striking Carvalho.
Having established a loose stranglehold on the contest, Chelsea tightened its grip within eight minutes of the restart.
Lampard had already gone close once after Joe Cole's shot had been deflected into his path but City failed to heed the warning, offering its opponent far too much space down the middle of the field.
The move took Chelsea deep inside home territory and after skipping on to Florent Malouda's pass, Lampard surged past Richard Dunne before burying his shot into the bottom corner.
Stephen Ireland and Wright-Phillips created chances for each other but were unable to take them as City tried to find a way back into the contest, Carvalho excelling on both occasions.
But Chelsea was the better side, with Anelka denied a clear penalty when he was pushed over by Micah Richards, only for referee Mark Halsey to wave away the appeals.
And 20 minutes from time, Chelsea produced the killer blow as Joe Cole sent Anelka clear with a superb pass. With only Hart to beat once more, this time Anelka made no mistake, slipping the ball under the advancing City keeper.
Before City could kick-off again, Scolari sent on Didier Drogba.
The delirious Chelsea fans launched into a chant of 'What a waste of money', which was premature in two senses given City are one game into a new era, albeit now aware of the mountain of work that lies ahead and Terry was sent off 13 minutes from time.
Terry's professional foul was clear enough after Deco sold the England skipper short with a lay-off but Halsey presumably failed to notice Carvalho stood at least two yards back as Jo was wrestled to the ground but what do you expect when you've got a proven moron in charge of a top flight game.
The club will surely appeal against the ridiculous decision.
It was a mistake Terry could well do without, although that was the only blot on Chelsea's day. The same could not be said for its host.
It was a mistake Terry could well do without, although that was the only blot on Chelsea's day. The same could not be said for its host.