The Red Devils face their local rivals and league leaders at the Etihad Stadium on Sunday afternoon.
Mourinho’s troops go into the match nine points behind Pep Guardiola’s side, who have yet to taste defeat in the league this season.
Defeat to City would essentially end United’s chances of lifting the Premier League title this campaign, a trophy they haven’t won since the 2012-13 season.
Mourinho is well aware of that fact and thus will adopt an attacking approach to Sunday’s match.
“We are going to try (win), “ the Portuguese said in his pre-match press conference.
“I cannot say we are going to be successful in our motivations, in our desire, but we played two difficult matches away against two very good teams, Chelsea and Juventus, and we managed to get good results.
“Even if the good results were not in our pockets, the performances were there, the positive attitude was there.
“So we are going to try but City are a very powerful team.
“If we draw the gap is still nine points, if we lose it’s 12, so I don’t think that is the way to look at the match.
“We have to just think about the match, is difficult enough as an isolated event, if you want to put that match into the context of where we are and where we can be.
“I want to play it as an isolated match, a difficult match against a difficult team, but they will also think it’s a difficult match for them.”
United have no new injury concerns ahead of their trip to the Eastlands, which comes on the back of a 2-1 win over Italian champions Juventus.
Romelu Lukaku missed Thursday’s win in Turin with a muscle strain but has resumed training and will be assessed tomorrow.
“Lukaku is training with the team this morning,” said Mourinho.
”If the answer is positive and we have of course one more session tomorrow, if the answer is positive he is ready but he trains with the team I don’t know his answer.”
Missed Manchester United’s 2-1 win over Juventus? Click here for an in-depth play-by-play of all the action at the Allianz Stadium.