To be honest, I am very surprised that Atalanta can be beaten by Fiorentina, especially since Fiorentina has been abandoned by Dusan Vlahovic.
Even Fiorentina got a red card in that match, but Atalanta did not take advantage of the advantages they had. But Fiorentina, who only played with 10 men since the 79th minute, was able to score the winning goal before the match ended. In that match Krzysztof Piatek played extraordinary by scoring two goals and could replace the role left by Vlahovic. Even though Piatek had failed with AC Milan, but now he can play extraordinary with Fiorentina. Hopefully Krzysztof Piatek can play well until the end of this season, and help Fiorentina to win many games.
It was "one of those days" for Atalanta if you ask me. Fiorentina is not a bad team, and even with the sale of their (probably best) player, they are still not suddenly horrible. However, Atalanta had chances that they couldn't convert to score and that was one of the main reasons for the time being.
I would have to say it is not really that much of a big deal for them, it is definitely not a great deal of upset to lose it, after all I expected them to lose a bit later but still lose and not with the cup. Which means that they already had no chance so they will get an early break, good for the players so they wouldn't have to get tired for so many more games.