Manuel Pellegrini was an emphatic winner in the battle of the Manchester derby debutants in the dugout on Sunday, as his side ruthlessly took apart David Moyes' reigning champions at the Etihad Stadium.Sergio Aguero opened the scoring in impressive fashion as he volleyed home early in the first half, before Yaya Toure forced the ball over the line just before the break to put City firmly in the ascendency.And, after another well-taken goal from Aguero - his fifth in six derby appearances - Samir Nasri completed the rout with 50 minutes gone as he sent a side-footed effort past the helpless David de Gea.
A late consolation goal from Wayne Rooney, which came courtesy of a brilliant free-kick, will have done little to lighten the mood among the United camp ahead of a midweek League Cup clash with fierce rivals Liverpool. The absence of Robin van Persie from the visitors' squad made headlines, with the prolific Dutchman omitted with a groin strain. And, although United were boosted by the return of Danny Welbeck, they were faced with the unenviable task of keeping an opposition pairing of Alvaro Negredo and Aguero quiet at the other end.Their chances of doing so appeared slim in the opening exchanges, as City began with impressive fluency despite the frenetic nature of the occasion.And they were rewarded for their endeavour after just 16 minutes when Aguero opened the scoring with a fabulous left-footed finish from inside the box. The Argentinian had plenty of work still to do after Aleksandar Kolarov had picked up the ball from Nasri on the overlap before crossing, but he controlled his volley beautifully to give the hosts the lead.Kolarov's adventurous running from full-back caused problems again a few moments later, as the Serbian went down in the area following a challenge from Chris Smalling, but referee Howard Webb showed little interest in awarding a penalty.Despite a lack of further breakthroughs, City continued to dominate possession, with the frustration of the visitors clearly evident when Rooney picked up a needless booking. The England international was given short shrift by the dominate City centre-back pairing of Matija Nastasic and Vincent Kompany in the aftermath, and Antonio Valencia's woeful effort from the edge of the box was the nearest United went to getting back into the game.Their hopes of taking anything from the game were severely dented on the stroke of half-time, as Negredo rose highest to flick on a corner and the unmarked Toure reacted quickly to divert the ball in off his knee from close range.Moyes could at least take solace from the fact that the interval offered an opportunity to disrupt City's dominance, but just two minutes into the second half the hosts grabbed a third. Negredo was the provider again, the Spaniard holding up the ball brilliantly under the attentions of Nemanja Vidic in the box before turning and teeing up Aguero for a close-range volley he could hardly miss.And City fans already in dreamland saw their day get even better just three minutes later, as Kompany's rampaging run from the back ended in a lofted cross that Nasri emphatically turned home at the back post.The hosts were happy to concede possession to United and attack on the counter given the size of their lead, but a long-distance effort from Marouane Fellaini, which Joe Hart easily kept out, was the best the visitors could muster despite controlling the ball for long periods.United's day was perhaps best summed up by a flurry of activity in the opposition goalmouth that saw Patrice Evra hit the post and Rooney somehow denied by the legs of Hart when his well-struck effort from inside the box looked bound for the back of the net.The former Everton striker would get his goal eventually, however, curling in brilliantly from a set-piece to add some respectability to the scoreline for the visitors.