Guardiola is in his fourth season as manager at the Etihad Stadium but is yet to progress beyond the quarterfinal stage of Europe’s premier club competition.
The Citizens have however been the dominant force in England under Guardiola, winning two Premier League titles, two League Cups and one FA Cup.
Guardiola’s task of bringing the Champions League to the Etihad could not have been made harder after they were drawn against record 13-time champions Real Madrid in the round of 16 stage of the competition.
Despite enjoying success in England, Guardiola believes Champions League failure will be a stain on his reputation.
"Winning a certain way is what helps you to win the titles," he said ahead of Sunday's Premier League meeting with Tottenham. "We believe we can play in that way. But we will see at the end.
"Of course, here we will be judged not for the certain way [we play] but for the titles we win. That is the truth. It is as simple as that.
"We believe in this way. Last season was an extraordinary season for us and the people say, 'yeah, but you didn't win the Champions League'.
"That is why I will be judged - if we don't win the Champions League it will be a failure in my period here in Manchester. I know that."
Guardiola has not won the Champions League since leading Barcelona to the 2011 trophy.
