Atalanta has been pretty good recently. Unlike Milan, they've looked sharper and manged to dominate by far. Milan is going through a good form lately (based on results), but I think they've been more lucky than anything else. A win is a win, but in some occasions l.e against Frosinone and Udinese, they could have easily dropped points.
It's going to be difficult for both teams in the next weekend, but if I'd have to predict, I'd definitely say Atalanta's performances over the past few matches, give them an edge over Milan.
In fact, I can see even us having a difficult task against them. We're probably gonna consume lots of energy in CL game, and then we'll have to play away from home against Lecce, which is far from an easy task. At least, we're going through an entertaining period in the league. Every top team is going to have difficult matches in the next few weeks.