From Juventus performance in their recent matches,it shows that they are capable of winning Sevilla. Some of Juventus players are facing injury but I don't think that this will be a problem for them not to smack Sevilla's ass in the semifinals.
Though, Sevilla shouldn't be underestimated in this match,if not Sevilla will win the match. We saw how it happened with Manchester united,how it ended. Sevilla might have a poor performance in their domestic league but we shouldn't use this to judge their performance in Eurpoa because it comprises of various clubs from various leagues. Let's not also forget that Sevilla is Europa's favourite.
Juventus are a quality team, but they shouldn't underestimate Sevilla. I don't think it's a worry to say Sevilla is the team that will go through to the final after they managed to prove their quality against Manchester United. Sevilla performed so well and dominated, so Juventus should be able to realize how good Sevilla is.
So far Sevilla have also managed to rank 12th in the La Liga standings since they improved their form. Sevilla won their last 3/5 matches while they only had 1 loss and 1 draw. Juventus actually suffered 3 consecutive defeats in Serie A in their last 3 matches.