Henrikh Mkhitaryan and Luke Shaw will both be absent, but Zlatan Ibrahimovic will start as United look to recover from their opening group defeat to Feyenoord.
“It is very important,” said Mourinho, who intends to play a strong team. “To be honest I think we have to win.
“If we don’t win we have four matches and we would have to win all of the last four matches, which is difficult. I think tomorrow it is very important that we win the game.”