City are yet to progress beyond the quarter-finals since Guardiola joined in 2016 and the coach knows he will be criticised if he is unable to deliver the club's maiden Champions League trophy.
He said: "If I retire now, or in five or ten years, what happened in my career, it was completely unexpected when I started.
"I’m most grateful to the clubs, for the players I’ve had, the way we played and the way we’ve done it.
"These are words and theories that make me so grateful and happy but this is a business.
"And the business is to win. If we don’t win, I’ll be a failure. And if we win, it’ll be ‘How good is Pep!’ "
City have a chance to reach the semi-finals tonight (14.04.21) as they travel to Borussia Dortmund with a 2-1 lead in their quarter-final tie and Guardiola explained that all of his players are desperate to progress in the competition.
He said: "Now is the time to make another step. Everyone wants it.
"The players want to do it again because they were sad when we were not able to go to the semi-finals and this is an opportunity to prove ourselves.
"Nobody’s going to give it to us. We have to win it.
"It depends on us. If we’re good, we’re going to do it.
"If we make mistakes like against Lyon, we give them the three goals... maybe we don’t have a chance to qualify, we’ll see."