The Champions League winners have lost three and drawn one of their past four friendly matches.
Ten goals have been conceded in that run, including three in the most recent defeat to Serie A side Napoli in Edinburgh.
Klopp does not know whether key trio Alisson, Mohamed Salah and Roberto Firmino - all of whom return to training this week - will be available for Sunday's clash against City at Wembley and admitted his team are unlikely to be at full capacity.
But the German is not prepared to accept anything less than a competitive performance.
"I don't think we can expect to play our best game of the season," Klopp said.
"That's how it is with the pre-season we've had, but we have a long season after that. But it's not about that, it's about winning a football game and that's what we will try. There are different ways to do that and we hope to find one.
"I don't know exactly why people play this competition if [they think] it means nothing.
"I won it five times in Germany and nobody mentions it, but we play it every year. If you win, nobody cares. If you lose, some care.
"It's a game we play against City and that's the most difficult game of the season in every season, so we have to be ready and it's a good test for the things which are there in that moment.
"We have to make sure we defend in a pretty good way because if you don't defend well against City we could get a proper knock, and that's not the idea of the game."
Though adamant the outcome will not chart a course for Liverpool's season, Klopp bristled at the idea of the Community Shield being considered a glorified friendly.
"[To call it a] 'curtain-raiser' is unbelievable," he said.
"We try to be as ready as possible. If we had eight players available, for example, I would like to try to win it. It's a final."