The defeat against Atalanta is sometimes surprising and I see that the condition of the Liverpool team is not doing well because of the unsatisfactory results they got in the Premier League last weekend against Man United.
In football there are very often surprises, especially in the Europa League, almost every season there are big surprises and this season I think Liverpool's defeat was quite a big surprise because the Liverpool team is quite the favorite to win the Europa League title this season but in fact they are likely to eliminated in the quarterfinals.
Liverpool did not underestimate Atalanta, but they were too confident because at the start of the first half, Liverpool did have several good opportunities and they dominated the game. Even when Atalanta managed to score their first goal, Liverpool still looked quite confident, as if they believed they could catch up. But the situation really changed when Atalanta got their second goal, which we can see that Liverpool are starting to lose their rhythm and they look quite frustrated.
Liverpool will indeed face a tough path and their chances are not great but they still have that opportunity. As long as they still have a winning mentality, I think they can still make a comeback. In the 2018/19 Champions League season, Liverpool made a 4-0 comeback when playing against Barcelona, even though in the first leg they lost 0-3