I'm favouring Juventus for advancing to the semi finals. I'm aware of how successful Sporting are in this tournament.
However Arsenal and Juventus are not the same type of teams. Each of them has a special kind of game plan for themselves. Sporting's game somehow worked well in the rematch and it led them to even eliminate Arsenal which were the biggest favourite team for the Europa League title. But Juventus' style can be really boring and maybe problematic at the same time. If Juventus outweigh them they can get past them narrowly on aggregate.
Juventus have a bigger chance to be in the semifinals. They have no more chances in Serie A so for sure they will put the Europa League as their focus to get the title. Juventus is also one of the teams with a big chance of becoming a champion apart from Mamnchester United, of course. In my mind it is very likely that if not Manchester United will be able to win it, then Juventus will be able to win it.
The possibility of Juventus making it to the semifinals of the Europa League depends on them performance on the first leg of their match. Despite their inability to be in the top5 in their league due to the point deduction they had, they can still not make it to the semifinals they fail to play well by winning against their opponents in the quarterfinals.
Europa League is not always an easy game to predict the outcome of the results especially the round of 8 where them teams are looking up to getting to the finals if they make it pass this two stages and with Manchester United taking on Seville team who they have not beaten according to their record, we may likely see a change in the history this season because Seville is not in good form and Manchester United coach will be looking forward to breaking the record by winning them so hopefully it's going to be Manchester United for the final if they play well and win against Seville or Juventus will also make it to the finals.