Manchester United boss Ole Gunnar Solskjaer joined Manchester City counterpart Pep Guardiola in condemning the supporters who misbehaved during Wednesday's derby.
Nemanja Matic's strike earned United a 1-0 win at the Etihad Stadium, but it was not enough to prevent City advancing to the EFL Cup final with a 3-2 aggregate victory.
The game was somewhat marred by events in the stands as videos circulated on social media of City fans appearing to make aeroplane gestures in reference to the Munich air disaster.
Tempers frayed at full-time and a number of seats were allegedly ripped out and thrown from the away end.
Guardiola criticised the actions of those involved, a day after United executive vice-chairman Ed Woodward's house was attacked, and Solskjaer echoed the Catalan's views.
"Yeah, I've just got to stand behind Pep there," he said at his post-match news conference.
"You know, football is a game, it's a game we should all enjoy, spectators, the ones who watch it on telly, the ones who're playing.
"I keep telling the players every time, go out with a big smile and enjoy yourselves. Work hard, yes, and fans should always try to enjoy the games.
"We want rivalry, but let's keep it at a sane level. And let's make sure we eradicate that. I stand behind Pep there and I think all of us do. We want to make this a nice game."
City will face Aston Villa, 3-2 aggregate winners against Leicester City, in the Wembley final on March 1.