The Community Shield is an octagon 58cm across, spun from 4.2kg of sterling silver. It is also whatever you want it to be. It is, as the cliche has it, the traditional curtain-raiser to the English season, a chance to experiment with new formats of penalty shootout. It’s a fun day out at Wembley (although presumably increasingly less fun given how often the teams who habitually play in it have to get themselves to HA9 these days). If you’re José Mourinho or Pep Guardiola, it’s definitely a trophy. And if you’re Jürgen Klopp, it’s a very obvious waste of time. The Community Shield is highly polished and, as such, tends to reflect the person viewing it.

Much of what the Liverpool manager said about the Community Shield, of course, was true. If you win it, nobody really cares. That David Moyes led Manchester United to Shield glory did little to mitigate the disappointment of his reign at Old Trafford. That Arsenal won it in three of Arsène Wenger’s final four seasons at the club could not dispel the sense of stagnation.

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What is remembered is what goes wrong. Few recall that Liverpool beat Leeds in Wembley’s first penalty shootout in 1974, but the images of Kevin Keegan scrapping with Billy Bremner remain familiar to those of a certain vintage. David Seaman’s missed penalty in 1993 is far more memorable than Manchester United’s success. The 2015 Shield has its place in football history far less for Arsenal’s win than for the early warning it provided of a sloppily dressed, unshaven Mourinho’s imminent implosion. Lose the Community Shield and doubts can begin to assemble.

In one sense, it is vaguely absurd that Liverpool should seem vulnerable. They are the European champions, in a better position now, in terms of ownership, management and squad, than at any point since they last won the title. But this has been a difficult summer.

In the wider scheme of things it does not matter at all that Wednesday’s victory over Lyon was their first in seven pre-season games. Nobody thinks that last weekend’s 3-0 defeat against Napoli is any gauge of where Liverpool will be at the heart of the season. But they are indicative of where Liverpool are now and the indications are that they are some way off peaking.

To an extent, that is to be expected. Mohamed Salah, Sadio Mané, Naby Keïta, Roberto Firmino and Alisson were all involved in international tournaments this summer. So, if you count the Nations League, were Jordan Henderson, Trent Alexander-Arnold, Joe Gomez, Virgil van Dijk, Georginio Wijnaldum and Xherdan Shaqiri. Inevitably that has an impact on preparation. Many of them also played in the World Cup the previous summer. Klopp’s concern about the relentlessness of the schedule and what that means for his players is entirely understandable.

Nor has there been any fresh blood in the form of new signings. That goes against Bob Paisley’s dictum that you should always buy from a position of strength, both to ward off complacency and because there is nothing more likely to drive up the price than desperation, but in the circumstances it perhaps makes sense.

On the last three occasions Liverpool finished runners-up, they lost a key player: Nicolas Anelka, Xabi Alonso and Luis Suárez. Liverpool have not lost anybody other than the back-ups Alberto Moreno and Daniel Sturridge, and they have managed to sign a number of players to long-term deals. Crucially, in that regard, this is a young squad. Only three players are 30 or older and of them only James Milner would be considered a regular fixture in the starting lineup. The threat of a team growing old together does not apply here.

There is fresh blood, too, in the sense that Alex Oxlade-Chamberlain, having missed almost all of last season with a knee injury, is back, albeit he is a doubt for Sunday with a slight calf strain. Gomez and Keïta, equally, missed large chunks of last season through injury, while there may be more of an opportunity for the 19-year-old forward Rhian Brewster, who has had his own struggles with injury.

Liverpool’s is a young, developing squad, one attuned to Klopp’s way of doing things. It may be a little undercooked at the moment, but even five or six years ago teams tended to map their seasons out so they would not hit peak readiness until February or March. So why the tetchiness from Klopp? Why the sense of anxiety? Why the downplaying of the Community Shield?

Facebook Twitter Pinterest Jordan Henderson and Mohamed Salah of Liverpool during a game of table tennis in Evian-les-Bains earlier this week. Photograph: Andrew Powell/Liverpool FC via Getty Images

The problem is the old rules do not apply any more. Over the course of the past two seasons, City have in total dropped only 30 points, which means every game is vital. There is no place for a slow start in the Premier League. But it is not just about that. Liverpool’s pursuit of City last season was extraordinary.

The 97 points Liverpool accumulated represents a proportion of the available points that would have brought the title in 117 of the league’s 120 iterations. Yet even with all that grind, even with the late winners against Crystal Palace, Tottenham and Newcastle, it was not enough.

City versus Liverpool has the makings of a historic rivalry but for it to be so Liverpool are required to win a championship and it would be easy to imagine a team becoming discouraged, believing that this City cannot be caught. Their faith in themselves would be severely challenged were Guardiola’s defending champions to win comfortably at Wembley – even if there were mitigating factors.

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The truth is, there is no reason to believe City will be any less effective this season. They too had players involved in international tournaments this summer – five at the Africa Cup of Nations or Copa América and a further four at the Nations League – but the dynamic is different. A combination of unprecedented resources and a superlative coach has already made them dominant in ways English football has not experienced.

Klopp looks at the Community Shield and it reflects Liverpool’s doubts. Guardiola looks at it and sees another prize, the continued acquisition of which is the only thing that might answer his own intensity and ambition, and the needs of his owners.