@ife2020 if you had seen the last math between these two sides then youll know that Ac Milan was the better team between these two sides, and hence I dont expect Manchester United to win this game easily. Furthermore its normal for teams playing in the Europa League to have these kind of headaches, and that is why these teams have a big squad of players whom they can rotate and aim for best results.
I think it is quite obvious that it is not easy to decide which team could be better or worse. Milan was doing great and United was not doing that great during that period and that is why Milan managed to get a tie at away game, but now they are at home, which doesn't mean that United has to lose, if United got a tie at home that means they could get a tie at away as well who knows.
I believe it is going to be a bit different, I believe it is going to be a bit tough game, it will not be a game we could easily say who wins before the final whistle, teams will play hard, I do not see any team winning 3-0 or something, but it is still going to be a big challenge.
Aside from this game and rangers game, all other games would probably go to first games winners as well, that looks like more likely possibility. It is going to be difficult for many of them but it will probably happen.