Atalanta will not be able to withstand Liverpool pressure when the time comes. This is because Liverpool is in their super form, and they need to win Atalanta for them to remain in the league. Currently, we can see that it is only Liverpool and Leverkusen that I can say will reach the final stage, amd that makes Atalanta incapable to stop them from victory both at home and away. Klopp needs more trophy for him to use an a sendforth gift to Liverpool, because this is his last season with them. No matter how good Atalanta is, which I know that their performance is not consistent, they can never win Liverpool this season.
Although Liverpool is currently playing far better than Atalanta, but we shouldn't assume that just because Liverpool defeated Sparta Prague with plenty goals, they would easily defeat Atalanta. Despite their inconsistent play this season, Atalanta's performance in their league this season was too little to compete with Liverpool's in terms of play. Liverpool's goal this season is to win more trophies, after been eliminated from the FA Cup, this is the only chance they have because Manchester city and Arsenal have make Premier league difficult for them. I believe Liverpool will not let Klopp down in order to win their Europa games and advance to the final, which is their only opportunity to win more trophies this season.
Liverpool have a better chance of winning than Atalanta. They will host the first leg, in my opinion, which is the best opportunity to score a lot of goals at home, because when Liverpool lead the first leg with many goals, Atalanta cannot win them at home in the second leg, despite the pressure they make.