Manuel Pellegrini's side have the destination of a second championship in three seasons in their own hands courtesy of a comfortable win over their neighbours. They are three points behind leaders Chelsea, but have two games in hand on Jose Mourinho's side.
They were never truly tested against a United side who again looked worryingly off the pace only a fortnight after they were given a similar 3-0 chastening by Liverpool.
Dzeko nudged the ball into the net for the opening goal on 45 seconds after Samir Nasri's shot had come back off a post before he eluded Rio Ferdinnad to volley Nasri's corner into the net on 56 minutes.
City were in control for large swathes of the second period, and gave the scoreline a truer polish when Yaya Toure drove a shot low into the corner of the net with one minute remaining after the ball broke off Phil Jones from a James Milner cross.
David Moyes' United remain in seventh place in the standings, 18 points behind leaders Chelsea. They were again exposed as a side lacking true pace and mobility in key areas.
Consider this awful stat which just about sums up a season gone badly wrong in the league: Wilfried Zaha - who was not party to this defeat - Marouane Fellaini and Juan Mata were purchased for a total of £82 million, but have not scored a goal for the club this season.
1' - DZEKO OPENER: Dzeko slams the ball into empty net after Nasri saw a shot come back off a post. A brilliant start from City. What a dream start to the evening. United all over the place in defence.
17' - DE GEA DENIES SILVA: De Gea forced to come up with a timely stop to deny Silva the second goal. He is wondering what is happening here. Super stop by De Dea.
29' - FELLAINI FORTUNATE TO AVOID RED CARD: Fellaini goes into the book for a late elbow on Zabaleta challenging for a loose ball. Again, fortunate to avoid a red for that. Looked pretty dismal.
37' - MATA CLEARS THE BAR: Mata lifts the ball over the bar from 15 yards after Rooney had failed to connect with the Rafael cross. Great chance. Not taken. And on we go here.
52' - FERNANDINHO SOMEHOW MISSES: Kompany rises above Fellaini from the corner. Ball comes to Fernandinho, but he can't direct the ball on goal with his reaction header. How did that not go in?
56' - DZEKO ADDS THE SECOND GOAL: Dzeko nudges the ball into the net from the Nasri corner. Fine volley. Ferdinand well off the pace in trying to mark the forward.
69' - HART SAVE: Rafael with the cross towards Welbeck. Fine backheel, but superb stop by Hart to stand tall. United almost handed a lifeline.
89' - TOURE FINISHES MATTERS OFF: Toure drives the ball low and hard into the corner of the net. Ball breaks to him off Jones from the Milner cross. A 3-0 lead for City. Game over.
Man United lose their 10th PL match of the season, the most they have lost in a single Premier League campaign (9 in 2001/02 and 2003/04). They last lost 10 matches in a top flight season in 1990/91, when they finished sixth in the old Division One.
Man United are only the fifth reigning top flight champions to lose six of their opening 15 home matches the following season, after Ipswich (7 in 1962/63), Burnley (6 in 1960/61) and Liverpool (6 in both 1901/02 and 1906/07).
Man City win three consecutive top flight matches at Old Trafford for the first time since winning five in a row from March 1968 to April 1972.
Man City win three top flight matches in a row against Man United for the first time since March 1969 to December 1970 (4 matches).
Wilfried Zaha, Marouane Fellaini and Juan Mata were purchased for a total of £82 million, but have not scored a goal for United this season.
TALKING POINT: Will City go on from here to win the Premier League? Can't judge them on this win. United are fairly poor side considering what is expected of them. City were impressive here, but were not truly tested. Which is a sad indictment on the state of United. It is safe to say it is between City, Chelsea and Liverpool. Would be foolhardy to make too many rash predictions with a win over United.
MAN OF THE MATCH
Edin Dzeko (Manchester City): Two fine goals from the forward, and some superb movement up front. An accomplished performance, but City had excellent performers all over the park against a fairly mediocre home side.
Manchester United: De Gea 7, Rafael 6, Ferdinand 4, Jones 5, Evra 5, Carrick 5, Cleverley 5, Fellaini 4, Mata 6, Welbeck 6, Rooney 6. Subs: Kagawa 6, Valencia 6, Hernandez 6.
Manchester City: Hart 7, Zabaleta 7, Kompany 8, Demichelis 7, Clichy 7, Toure 8, Fernandinho 8, Nasri 8, Silva 8, Navas 7, Dzeko 8. Subs: Milner 7, Garcia 6, Negredo 6.
THE MATCH IN A TWEET
- Sports & Recreation
- Manchester City
- Manchester United
- Edin Dzeko
- Marouane Fellaini
- Premier League
- James Milner
- Yaya Toure