Sevilla are always strong at home and they can likely repeat what they did to united at home,but I will say that Juventus players and not united players and if you put into consideration, Sevilla scored first before the goal was equalise on the extra time by Gatti. This also shows that Juventus wouldn't take the second leg match easy,since they have been motivated by their equalising goal. Juventus will still have it at the back of their mind that they can qualify to the finals.
As long as Allegri is aware that his scheme for the first leg is lacking I think this will be another condition where they will really be able to make a good match for Juventus in the second leg.
Yesterday's Juventus problem was that they were very lacking in finishing which made their opportunities completely wasted.
On the other hand, the conceded goals during the counter-attack that Sevilla carried out should also be noticed because in this case Juventus are still completely unbalanced in anticipating counter-attacks.
Of course, Mourinho won't let them lose, Roma will struggle enough in Serie A, and they will target the Europa League trophy at this time. Mourinho knows exactly what he has to do for it all.
If Roma get to the finals, I will bet fully that Roma will win against whichever team they face. The special one has been in the finals of many competitions as coach of the underdog team but somehow with his brilliant coaching tactics, he does the job even if not cleanly, but he does the Job. I will like to see Roma win the Europa for the sake of the coach, the players and the supporters of the club who have believed in them.
Actually, even though they won in the first leg, I still can't be sure they will win easily, especially for the second leg. It will still be a little more difficult if you look at their statistics in the first leg.
On the other hand, don't forget that Sevilla and Juventus also have the same conditions and making sure Roma win early is a mistake I think.