After their goalless draw with Liverpool on Monday, United must now face the Turkish side, Chelsea and Manchester City in the space of a week and that had led to suggestions that Mourinho would play a second-string side in Europe.
However, the Portuguese claims that he will need to name a strong starting lineup against opponents who currently top Group A.
The 53-year-old told reporters: "If we play with a team that is not good and strong we won't have a chance.
"Everyone knows the Turkish league is getting better and some of the teams not coming from Istanbul are coming step by step."
United have recorded three points from their opening two fixtures in the competition.