I myself was quite surprised that Atalanta could lose to Club Brugge in the first match and this, Atalanta must be hurt because their defeat occurred because of a penalty kick in the last minute in the second half of the match which made this match have to accept defeat for Atalanta if there was no violation it might have only ended in a draw, Club Brugge was lucky to get a violation in the final minutes of the match which brought them victory in the first leg, and I also think that Atalanta will most likely take revenge in the second leg, they have big ambitions for the champions league this season.
I am not too surprised by Atalanta's defeat. Although I considered Atalanta as the favorite in this match. But for a long time we have been seeing irregular and weak performance from Atalanta. Atalanta's performance in Serie A matches was also quite irregular.
This was Club Brugge's home match. And in the home match Brugge's players played very well. However, Club Brugge scored their second goal from a penalty after 90 minutes. The team was very lucky. Otherwise, Club Brugge would not have been able to secure the victory by scoring a goal in the last minute.
Atalanta played well in this match even though they lost because of a penalty goal at the end of the match but overall Atalanta played well and even they were able to control the game but they were unlucky in the first leg and for the second leg later where Atalanta will play at home of course has a very big chance to be able to turn things around, I think Atalanta is still very favored to be able to qualify for the next round.
Regarding the inconsistency of Atalanta's performance in domestic league matches, I think it cannot be used as a reference because of course each team has much greater motivation in the Champion League match.