The Belgian remained an unused sub as Kylian Mbappe’s hat-trick sealed Madrid’s 6-3 aggregate win in the Champions League play-offs.
De Bruyne had played 84 minutes in the first leg, but Guardiola opted for other midfield options at the Bernabeu.
On why he chose to leave out De Bruyne for such a big game, Guardiola ‘stated: Decisions. My decision.
'Yeah, of course (he can still play in big games), he played against Madrid at home, of course he can play...'
Guardiola added: 'The relationship with Kevin De Bruyne is exceptional. I can't be thankful enough for what he's done for me, the team, everyone. It's just a decision.
'Normally I don't speak with players, not just Kevin, on why they don't play. They don't ask me why when I decide to let them play from the beginning or during.
'It's just a decision from what I've seen, for many reasons, a few. Never ever is it personal, never ever I'm upset.
'Also Jeremy (Doku) didn't play and his last game was in Ipswich, (when he) played unbelievable, and after that was injured.
'But maybe for the demands, the way we now need to play because of the absences or strengths that we have and physicality and many things, we need a game of more control and not up and down.
'Don't tell me why. It's not personal, I decide the decisions, that's all, no more than that...'