I'd go further, we're already risking top4, if Atalanta wins this we absolutely will have to win against Milan if we want top4.
All the important stuff in Serie A besides CL places is already decided, the winner is Inter (+11 over 2nd place), the relegated sides are Crotone, Parma and Cagliari (-5 from Torino who have a game in hand) and the last EL spot is occupied by Roma (+11 over 8th place). So this game and the game against Milan are the deciding games for us, as all the other games we (and the other teams contending for top4) will be facing teams with no other motivation besides pride. Sure we and the others might drop points here and there (against Inter or Roma f.e.), but most of the games I expect 3 points going to the team that has something to play for.