Sevilla is the luckiest team I saw and they didn't have good players or even a good coach this season, also in most of the games, Sevilla couldn't even have a good performance and the only reason for them to win this title was using the mistakes other teams had and they also had enough luck to win the hardest games against strongest teams like Manchester United in this season.
That's why I can blame Roma and Mourinho for anything when they lost the game against Sevilla.
Sevilla was not lucky for winning the Europa League because they really deserve it but I think they were lucky not to have finished the season in the bottom place because they had a very poor outing this season they just managed to win few games with aver poor performance in every game I watched them this season. Did they win the Europa League using other teams mistake I guess no rather they saw the trophy as the only remedy to their problems and when they got to the knock out stages they changed their playing pattern and that alone helped them to defeat the big teams you mentioned and I think they are like owners of Europa because they never lost in the finals and winning it was a dream come true to so many fans.