I assume they will suffer a lot in it and that Atalanta might make them lose some points and this will be a chaotic scenario!
Now even a Milan draw won't be sufficient for Inter since Milan needs 1 draw + 1 win at least to qualify.
They both are tough games indeed. Atalanta seem to be a more serious opponent considering the recent performances actually but we never know how eager Sassuolo are going to play against Milan. Therefore Milan should get prepared equally well for both of them. They only need four points to become the champions in the league now. If Milan manage to destroy Atalanta first, then things will be much easier. And I believe they can do it.
Atalanta is having a really bad season this season. They have achieved good rankings in recent years, and have also played very attractive football. Were even close to the semi-finals of the Champions League once. This is a season to quickly forget, and of course the same goes for Juventus. What strikes me most about Atalanta is the quality of the players, which is mediocre and yet they normally function well as a team.