Pep Guardiola emerged victorious from his first Premier League meeting with Jose Mourinho as Manchester City secured a fully deserved victory in a frantic Old Trafford derby.
Kevin de Bruyne's composed finish and Kelechi Iheanacho's tap in- after the outstanding Belgian had hit a post- put the visitors in complete command as they outclassed Mourinho's new-look side for much of the opening half.
The hosts were handed a lifeline just before the break when City's debutant keeper Claudio Bravo summed up his desperately uncertain display by dropping a free-kick to allow Zlatan Ibrahimovic to halve the deficit.
United mounted an aerial siege in front of the Stretford End in an improved second half showing, but City held firm to extend their 100% record and inflict a first defeat of the season on the hosts.
Paul Pogba went close with an early sighter from 20 yards but, despite missing influential Argentine Sergio Aguero through suspension, the visitors flew out of the traps and went ahead after 15 minutes.
For all Guardiola's famed "tiki taka" style, the goal came from Aleksandar Kolarov's long punt downfield which was flicked on by Iheanacho into the path of De Bruyne who raced through and fired in a well-taken finish.
City did not allow Mourinho's side to get anywhere near them and quickly doubled their advantage nine minutes before the break with De Bruyne again at the heart of things.
The brilliant playmaker struck the post from a narrow angle but the ball fell perfectly for Iheanacho who was left with the simplest of finishes from close range.
By now, the visitors were well on top but United rallied and finally gained a foothold in the match when Bravo fumbled Antonio Valencia's set piece and Ibrahimovic was on hand to volley home three minutes before the break.
Wayne Rooney picked out the Swede to head straight at Bravo before Mourinho sent on Marcus Rashford and Ander Herrera at the interval in an attempt to spark United into life.
It took Rashford less than a minute to make an impact as he found Ibrahimovic to volley over the top, and the young striker then had a goal ruled out after his shot hit Zlatan - who was standing marginally offside - on its way in.
David De Gea saved superbly from Fernandinho, Ibrahimovic volleyed wide and Rooney had a possible penalty turned down before De Bruyne again hit a post in an increasingly end to end encounter.
Despite their best efforts - and five minutes of stoppage time - United ran out of time and City deservedly held on to take the spoils (and bragging rights) in the 172nd Manchester derby.
United Faithful Man of the Match: Marouane Fellaini