Henrikh Mkhitaryan scored the game's only goal as the Red Devils coasted into the last 16 by four goals to nil on aggregate.
"Everything was under control, solid, focused, professional. Obviously the first goal kills every hope. We still like to win the game. I told the players if someone gives me a 2-1 victory it is not enough. I always want the best possible result," BBC Sport quotes Mourinho as saying.
"I have to give the right message to the players and the right message is to play with a strong team and have a bench with options. We knew it would be difficult. It was important to play solid and to have complete control of the game."
The draw for the last 16 of the Europa League takes place on Friday.