City were hammered 5-1 by Arsenal on Sunday night, with Guardiola conceding his team collapsed in the final quarter of the game.
He said, "I only regret the last 25 minutes, we forgot to do what we should do, what we have done for 65/70 minutes. Of course it's a difficult game starting in this stadium, against that team in the first minutes it's happened many times this season.
"But after 10/15 minutes I think we took the game and played really, really, really, really good and we are in it after 1-1 and good momentum we pass to make the transition with Omar (Marmoush) and a deflection and the third goal.
"But after that, we then continued to do what you have to do in terms defensively and (be a) little bit more patient. and when you're playing that way they can run and of course at 3-1 they are comfortable, its more difficult. I regret the last 15/20 minutes, the rest was a really good game for our side. It's difficult to understand when you see the result but this is my feeling.
"It's happened all season, we are giving away too many things, we are aware this cannot happen, it happened. But we reacted really well and we played with personality and we defended so good and then with the ball we were a threat but unfortunately after the second happened, again many times we had the momentum. For the deflection and in other situations we conceded the goals.
"You have to overcome (it), you cannot lose the control, it's 90/95 minutes. You cannot finish in the way we played, we could've scored three more but the team has to be stable it doesn't matter what happened."