I think the two teams must respect each other and not underestimate each other because one of them is one step away from going to the European league finals this season. Maybe I think Sevilla is quite favorite from a historical point of view or even according to their calculations in the European league competition and Juventus did not give impressive results before heading to this match, but I'm pretty sure that Juventus will be able to overcome this problem. What is clear is that these two teams deserve to be in one place and I think both teams will try hard to secure their first win in the first leg later.
Underestimating would make any team lose against any team. You have to be constantly careful about something that would make sense, otherwise it is not going to really work in your favor and you would end up losing to a much worse team. There are 4 teams left, and all of them has to respect each other and consider that they could lose if they do not play right, which is true and that is why it is such a fun period.
When a team gets to as high as semi-finals, then there is no reason to think they may lose, they could be as good as it gets and we need to end up considering that as an option. I personally believe that we can't really make this go away, we need to endure the stress of not knowing who will win, and hope that our bets are profitable.