Pellegrini's men sit 12 points clear of Manchester United in the Barclays Premier League table, and the Chilean knows extending that advantage will both boost City's title hopes and hand a crushing blow to David Moyes' shaky hopes of reaching Europe.
But after years of acrimonious pre-match derby build-up, Pellegrini appears determined to build bridges - even conceding City still have significant work to do to emulate the sheer weight of history that sits in the red part of town.
Pellegrini said: "I think this club has been trying to work in the last four years to reduce the difference we have against important teams - against Manchester United, Chelsea and Arsenal, and in Europe as well.
"It is always important because when you have two important teams from the same city you always want to be the best team. But we are not just fighting against Manchester United and in some ways it doesn't matter."
Referring to a previous comment he made about City assuming top position in Manchester, Pellegrini added: "It was easy because I meant in this season, the best team is Manchester City because we were top of the table.
"But at the same moment I said we must recognise what Manchester United have done in the last 20 years.
"Of course all the other clubs expected United would be in the top positions in the table (this season), but for different reasons at this time they are not. But they continue to be a difficult team.
"It is difficult because for so many years the same person managed a team with his ideas. It is difficult to analyse without knowing it from the inside - but it was always going to be difficult to replace (Sir) Alex Ferguson."
Unsurprisingly Pellegrini also sought to play down suggestions his side will start as favourites when they head to Old Trafford looking to reduce the gap on leaders Chelsea, whom they currently trail by six points with three games in hand.
City's quest will be bolstered by the return of defender and captain Vincent Kompany after serving his one-game suspension for his sending-off at Hull, but striker Sergio Aguero is still ruled out.
Pellegrini added: "I don't think we are favourites in any game. We are in a good moment but we are playing against a big team in their own stadium so I don't think we are the favourites.
"Of course we always expect to go and win every game but I repeat, just because Manchester United have had a difficult season it does not mean we are going to win. We have to go there and play a very good game."
"You don't have problems in that sense, mentally or physically. We are just trying to fight for the title. I know we must go game by game and we just have to win on Tuesday and then at Arsenal on Saturday after that."
Meanwhile, Pellegrini took the opportunity to heap more praise on Yaya Toure, whose hat-trick against Fulham underlined why the City boss believes the Ivory Coast star is currently the best attacking midfielder in the world.
Pellegrini added: "At the moment because of the number of goals he has scored, of course. But I think Yaya is not just about the goals he has scored. He is a complete midfielder and he gives important assistance as well."