United roared back from two goals down to beat Pep Guardiola's City in this fixture last season to delay their neighbour's coronation as Premier League champions, but Herrera said recent history counted for nothing.
"We're still very close and who knows, maybe in the future we can play together again on the same team".
"It's a very good team, especially at home", the ever-improving Swedish centre-back said.
"I think there should be reaction and passion at the end of a match".
Manchester United's comeback win at Juventus evokes memories of Alex Ferguson era
Ander Herrera says Manchester City may be favourites for Sunday's derby but Manchester United remain the biggest side in the UK. It was not the best performance under Mourinho that some have rather hysterically suggested.
Anthony Martial is the man in form for United so they will need a big performance from him.
They meet regularly and have been spotted at restaurants in the city centre along with other players including United's Eric Bailly, Marouane Fellaini and City's Riyad Mahrez. But what is behind, I can not say. I can not say we will be successful in our motivations and desire, but we played two hard matches away against two very good teams, Chelsea and Juventus, and we managed to get good results. So from Juventus we don't bring important injuries.
United's ability to snatch late goals under former manager Alex Ferguson was one their most potent weapons, an ability they have not managed to display with any sort of regularity since the Scot retired.
So, we have to make sure we grow up not just in our approach, - because that I think is clear that the team is growing up - but also we have to grow up in our compactness and to start matches well.
Belgium striker Romelu Lukaku has missed United's past two matches with a muscle problem, but could return against City. But in this type of games, I would go for David Silva as he and Kevin De Bruyne are the two players who can pick out that final pass to split open a defence, who are sitting back and trying to frustrate them. We have of course one more session tomorrow, but if the answer is positive, he's ready.