It looks like the second leg matches for Juventus and Sporting will also be more interesting to watch because what you said might be true if the home team (Sporting) will try to outperform Juventus even though they are one goal behind on aggregate. And Juventus themselves must also have a pretty good strategy in this second leg because Juventus must know that the home team will play better to ensure they qualify for the next round.
Juventus celebrated their win in the first leg against Sporting like they had won the league, Sporting will be difficult to play in this second leg. Juventus still have to put in their best.
Manchester United have a major encouragement as Rashford who had groin problems, Sabitzer and Luke Shaw may likely play against Sevilla. They may not be fully fit for the game, but they are much needed to ensure Manchester United's victory in this important game, after loosing their advantage in the first leg.
https://www.bbc.com/sport/football/65322095