A 4-0 win in Switzerland in the first leg three weeks ago made qualification nearly a formality for a team that is 16 points clear in the Premier League and one of the favourites to win the Champions League.
City advanced 5-2 on aggregate and became the second English team through to the quarterfinals, after Liverpool from Tuesday. "My agent has not been in town", Guardiola told Sky Sports News.
He said (via Marca): "From tomorrow we'll be happy to have qualified, but in the second half we forgot to attack and forgot to play, to pass the ball".
"Mr Glenn has apologised, so okay", said Guardiola "But the first impression when I heard that is that it was because he didn't understand what the yellow ribbon means".
"The best example [of that being dangerous] was two days ago". Everyone is thinking about when we will win the title.
"Maybe it was because we had less pressure, that we had nothing to lose", suggested Elyounoussi.
"You have to be focused because Stoke away is always complicated".
The evening began positively for City, unbeaten in their last 12 Champions League home matches, when Brazilian Gabriel Jesus put them ahead in the eighth minute.
"What happens in the (Champions League) quarter-finals depends on our level in the Premier League", he said.
"I reviewed the game and we did quite well, well enough to go through".
"Any team that makes six changes may have problems but in the second-half, we thought we had finished the game".
"And we will see our chairman and be there".
England's Football Association on Friday fined Manchester City manager Pep Guardiola £20,000 ($27,700) for wearing a yellow ribbon in support of jailed Catalan independence leaders.
The City manager's deal runs out at the end of next season, and he has repeatedly refused to discuss in public whether he will extend it.
'Was not, is not, will not be in town in the next weeks'.