Guardiola has led City to six Premier League titles since joining the club in 2016, while he also won both La Liga and the Bundesliga three times apiece with Barcelona and Bayern Munich respectively.
This season is just the fourth time in his illustrious managerial career that he has failed to finish top of the league.
The Spaniard has had to contend with a lengthy injury list, contributing to City relinquishing their four-year hold on the top-flight trophy, and they were also knocked out of the Champions League at the play-off phase.
The 54-year-old called it the «most difficult» campaign in his time in coaching, adding: «When you don’t win, it’s more demanding in terms of emotionally and preparing [the team] and the mood.
«It has been more and more difficult than the previous seasons that we played for the winning for the titles.
«The people pay the tickets to come to the stadium and I had to prove myself again and again.
«I am disappointed in myself when it’s not going well, so when I retire and we review my career, I can say, ‘OK, I have been good or I have been bad, I could be better or I could be worse.’ But right now, the next game, I have to prove myself.»
City beat rivals Manchester United to claim the Community Shield last summer but between October and December the side endured a run of one victory in 13 games, which included nine defeats.
But they can end a disappointing season on a high by finishing in the top five, as well as having an FA Cup final to play for against Crystal Palace on Saturday 16 May.
«It’s a business, we have to win games,» said Guardiola «Otherwise, you cannot be here next time. We represent the people, represent the club — you have to do your job as best as possible
«And today, this season, we didn’t do that. we were in the highest standards and we dropped here. Even with that, I would say it could be worse.
«We were still there. I was there, the players were there. Not our best, but we didn’t give up.»
