Manchester City 0 Manchester Utd 1: CRISTIANO RONALDO may need to be convinced but, when the dust settles, Manchester United will cherish the day they reminded their nouveaux riches neighbours just who should be known, in the words of match-winner Wayne Rooney, as "the real kings of Manchester".

Ronaldo's red card removed some of the gloss but, ultimately, that kind of thing is only a minor irritation when you have just beaten the club who have been shouting from the rooftops about changing the order of world football.

A club with United's priorities will not mind too much, either, about the fine that will automatically be handed out by the Football Association as this was the second time this season they have collected six or more yellow cards in a match. Do not put money on United winning the Fair Play League but, equally, think twice before questioning whether they have the battling qualities to come from behind in this season's title race.

They won the 150th Mancunian derby because they passed the ball better and had a centre-forward who decided he had waited long enough to score the 100th goal of his career.

Rooney was the outstanding performer, although an honorary mention goes to Michael Carrick. Between them, they dictated the pattern of a game in which the margin of victory was flattering to Mark Hughes' team.

That's because, in part, of Robinho's inability to impose himself. This was his weakest game since moving to England and, at times, he looked as though he was struggling from an old ankle injury.

Stephen Ireland and Shaun Wright-Phillips, City's other main threats, flickered sporadically, and the home side did not really pose any threat until another Brazilian, Elano, came on at half-time.

His introduction with Pablo Zabaleta was an admission on Hughes' part that the first half had been horribly one-sided.

Rooney was having one of those days when he shimmered with menace every time he took the ball. Park Ji-Sung was busy and effective and Ronaldo started off in great form, always wanting the ball and full of positive running.

Rooney would be left to reflect on a hugely satisfying day's work, scoring the game's decisive goal after City's goalkeeper, Joe Hart, had parried Carrick's left-foot drive.

For Ronaldo, however, everything would change during the space of 10 second-half minutes.

His first aberration was to clip Wright-Phillips's heels, cutting short a counter-attack and earning him his first yellow card from Howard Webb. It could have turned into red if Webb had taken a dim view of Ronaldo sarcastically applauding the decision.

Instead, his exit was sealed when Rooney swung over a corner and the runaway favourite to be named European footballer of the year tonight inexplicably decided to bat down the ball with both hands.

Why he did it, only he will know. Ronaldo can be devastating in the air and the opportunity was there to have a go at goal. His argument was that he had been pushed by Micah Richards but there was minimal contact, certainly not enough to make him lose the trajectory of the ball. He took an age to leave the pitch and, on the way, complained he had tried to stop play after hearing what he thought was the referee's whistle. Again, it did not wash.

City's fans enjoyed the moment but it was a small victory. Hughes will look back on that moment, in the third minute of stoppage time, when a combination of Edwin van der Sar's left hand and Patrice Evra's boot blocked Richard Dunne's effort on the line, denying him an improbable equaliser. The home side will also reflect on Ireland hitting a post after Van der Sar's unconvincing punch just after the half-hour mark.

These, however, were isolated moments on a day when, for every chance that City created, United had three. Even after Dunne's late chance the team in red elegantly counter-attacked and, alert as ever, Rooney noticed Joe Hart was still running back after coming forward for the attack. The striker lofted a wonderfully measured shot from inside City's half, but the ball was in the air long enough for Hart to get back and stop it dropping just under the crossbar.

Even so, United are entitled to think they have reminded City of their place.

• Guardian Service