Asked if his players went too far, Guardiola said: "No. Definitely not.
"We were happy. We won a derby against Manchester United, one of the best rivals we have."
After the players and staff headed down the tunnel, it is understood Jose Mourinho complained outside the visitors' dressing room as he made his way to interviews.
In the ensuing row, the Portuguese had water and milk thrown at him while City coach Mikel Arteta suffered a cut head after he was hit by a plastic drinks bottle.
Guardiola said: "We celebrated. I think if United win a derby, they celebrate.
"But where? Inside the locker room. That's what we tried to do and we did.
"People have to understand that we were happy. I think all the teams around the world when they win a derby, they are so happy."
The Football Association said on Monday that both clubs have until Wednesday to reply to a request for their observations of the incident.
"After what happened, hopefully it cannot happen again," said Guardiola.
"What happened we will explain to the FA investigation. United will do the same.
"We will make a statement to the FA. I am not going to comment about that."