Atalanta have wiped out the winning results at the end of this season with a series of wins, I don't think they will underestimate Fiorentina even though it is possible that Atalanta only fielded their second tier players, after all it is also impossible that Atalanta will experience defeat in this match, because even though they have become Winning the UEL and qualifying for the UCL next season will certainly not make them complacent, they must finish all matches with a series of wins, especially against Fiorentina.
I think Atalanta will win against Fiorentina because for me Atalanta's strength is quite good this season and they managed to maintain their ranking in the standings this season well, Atalanta has certainly worked hard to become a strong team this season, I'm not sure they will think Despite Fiorentina, Atalanta will get the full three points from this match and complete a streak of consecutive wins to end the remaining matches at the end of this season well, clearly this match is still important for them.
Atalanta have been an improving side overtime. They've had some rough edges but their performance in the league is still seen. Even though they were not top trophy contenders, they have tried to stay in the domestic league instead of relegating. They played against Leverkusen in the final phase of the UEL and goodnews is they were been able to gather enough confidence and momentum for the game which put them in an advantageous spot of finishing with a tangible result regardless.
Atalanta also lost to Juventus in the Copa Italia finals which then left them to struggle solely for just the UEL trophy. Their opponent weren't really tough either. As the game had turned out in their favor, they therefore had a resounding confidence to face up their next opponent but at this point in time, they're left to dedicate all resources available and necessary to fighting hard to earn the victory.
Fiorentina on the other hand have been in between performances. Yes, generally this season, they've been more of a threat to teams too in all their games. They're a good side and there still is just a little chances to prove their mark, but they don't have to keep being in the dark, letting lower teams overpower them. Even though they will battle out with Atalanta a tough team, they should still struggle hard to keep a draw at least. The strategy should be redrawn, they've got to put in extra efforts to getting a better result than what they already have.