"They are so strong. This team together with the club, the money they have and this manager is exceptional. It is a good match, a good combination," said the German, as quoted by the Irish Independent.
"It makes them the biggest force at the moment - together with PSG - in world football. We have to battle and fight with them for different things in the league, and maybe in the Champions League at one point if it comes to that again."
The former Borussia Dortmund coach attributed his seven wins over Pep Guardiola to "courage and good luck" and expects City to come at them after last season's losses in the Champions League
"It is not that when I faced teams of Pep Guardiola I had a team of names that nobody knew and I had only met them the day before. The mix of quality and attitude is important," he added.
"What I know, because I know how I would be in that situation, is that they lost the quarter-finals against us last year and the league game here after a long run without a defeat and they want to respond," Jurgen Klopp concluded.