The United boss is without a number of players for the trip to his homeland, leading to him suggesting that it is obvious which players will take to the field at the Estadio da Luz.
United will once again be without long-term absentees Paul Pogba and Zlatan Ibrahimovic and whilst Luke Shaw and Marcos Rojo are nearing full fitness neither will be considered for this one.
Eric Bailly and Marouane Fellaini are also sidelined with injuries picked up on international duty.
Nevertheless, United go into the game as heavy favourites, they currently sit top of the group whilst Benfica remain rooted to the bottom having yet to pick up a single point in their two games so far.
Rui Vitoria's side haven't reached the knockout stage of the Champions League since 2013/14 and a victory for United would all but end their hopes of doing so for another season.
Benfica go into the game off the back of a 5-0 thrashing at the hands of Basel last time out, whilst United recorded a convincing victory over CSKA in Moscow in their last outing in the competition.