Manchester City must know they are making their mark. The club have collected the FA Cup, their first major trophy since 1976, and Roberto Mancini will have the full attention of all rivals this weekend, particularly since Sunday's Community Shield fixture at Wembley is a derby match, which should make this occasion more significant than usual.

It was notable that David Beckham, commenting recently on the rise of City, turned to the past when acclaiming his former employers. "They may be a threat for seasons to come," he said of City, "but United have the silverware over the last 20 years." That is beyond dispute but it will also be an irrelevance to City fans who may believe that their time is just beginning.

The side, of course, has not yet come close to being a blight on United, who won the Premier League last season and reached the Champions League final for the third time in four years. Nonetheless, the scale of the investment in City can only make even the shakiest of sense if the club is established among the most formidable in the world.

There is a Champions League campaign to come, but City so far have done most for their reputation in the FA Cup. The semi-final may have carried the deepest meaning since United were the losers, overcome following a rare error by the now retired Edwin van der Sar. Yaya Touré capitalised because of the greater licence that Mancini had given to a player sometimes known as a defensive midfielder.

The Italian does not seem much of a romantic and was surely right to take the commonsense view that he should start by constructing a solid structure. That conservatism was reflected in a tally of just 60 goals in the Premier League. United, Chelsea and Arsenal had totals of 78, 69 and 72 respectively. This is far more than an issue of style. City, if they are to advance further, will have to confirm their incisiveness week by week if they are to last the pace.

After gorging themselves in the transfer market, the club now look committed to a healthier diet. In that context, it was notable that an exception was made in the case of Sergio Agüero, bought for £38m from Atlético Madrid. The Argentinian, who has been injured and is expected to be a substitute at Wembley, can be regarded as a replacement for the unsettled Carlos Tevez, but it would be no misfortune for Mancini to have both of them on the books. With the marvellous midfielder David Silva at work, entertainment levels could climb steeply.

Conjecture does not seem to whirl around United to such an extent. And when it does there is not so great a tone of significance. The air of continuity is, of course, a longevity dividend arising from Sir Alex Ferguson's 25 years at the club. Paul Scholes has gone, but he had been edged towards the margins for some time. Edwin van der Sar has also retired, with United veering to the opposite extreme from the veteran by spending £18.3m on Atlético Madrid's 20-year-old goalkeeper David de Gea.

There was outlay, too, on the Blackburn Rovers defender Phil Jones, who could well see considerable action in his first United season if Rio Ferdinand is again hampered by injury. Ashley Young is also on the Old Trafford books now, but there is a sense that United need a little more not simply to present the crowd with a spectacle, but also to upgrade the squad for the European scene. It is no surprise that murmurs continue about a bid for Inter's Wesley Sneijder. The Dutchman epitomises the extra dimension that United will need if they are going to continue to be so effective in the Champions League.

In the domestic arena the stress may not be so great as in recent times, but there are unknown quantities for United and City to consider with care. André Villas-Boas's effect on Chelsea is yet to be gauged and while the squad could do with some rejuvenation, his work at Porto suggests that there will be an impact sooner or later. For the moment, the Community Shield reflects a sense that the contest between the Mancunian clubs will continue through all the other tournaments as well.