Guardiola accepts that there was always going to be a reaction this season after his team won back-to-back titles with a combined total of 198 points.
He said: “What my team did over the last two seasons was incredible. I don't have any doubts about them because I know what can happen the season after you are champions.
“Liverpool obviously will be champions but they would be champions in Spain, champions in Italy, champions in Germany. They would be champions everywhere.
“The have 22 victories and one draw from 23 games. It is impossible to handle that even in your best moments.
“We have had decent results this season. We would be fighting for the title in Spain, Germany and Italy with the points we have.
“But Liverpool are just fantastic, phenomenal, overwhelming, with what they have done.
“But in terms of mentality, this team is incredible."
“Honestly, it is one of the best I have ever handled or faced in my career. That is why I am so proud."