I think Juventus are still under a big threat by Sporting in this round. Because despite getting that win with a 1-0 score in the first leg they are still not in a very advantageous situation. Sporting performed very well in that match and Juventus were really lucky to not even lose that. Juventus somehow managed to do their usual trick and secured a 1-0 lead until the end of the match. But they might have bigger difficulties now.
Because Sporting are going to play before their supporters above all else. This can give them extra confidence about a comeback in this round. Besides if they can manage to be even more in control of match this time they can score an early goal to take the lead too. Juventus will need to do their best defending here. As things aren't going well in the Serie A for them they really need the win the Europa League title to be able to qualify for the Champions League again.