Difficult or not , I think Arsenal has the first chance to win Europa League because if we take a closer look, they finished Group A with 5 wins out of 6 games and have a +5 goal difference so that tell us clearly that they like to score a lot and once they score , they won't lose the game. Now , in 2nd place , I might give it to Betis Sevilla and not Man.United. Why ? Well , United are really looking like a complete team ? I say no. Betis on the other hand , have played with almost same players for 3 years now or even and this makes them a strong team and very united with each other to complete their goal to win an European Competition.
I also have an opinion that Arsenal will win the European league this season and that is not without reason considering their hard work so as to form strong character for Arsenal's players to date. The role of coach Mikel arteta is also very important to make all the players compact and solid in every match. Even in their regular league, Arsenal managed to break the consistency of Man City and maybe it was destiny for Arsenal to win the title.
Right now, all facts and figures are going into Arsenal favour for winning the European title even we have to wait for few outputs which are important in coming weeks but their performance and quality is surely at his best in both competitions even few are feeling injury of Gabriel Jesus is going to have impact on their performance, but they are already having good backups and their quality is surely still good because from the start of this season Mikel Arteta done good job and maintain his quality at his best which is helping them in Premier League as well.
But, now we are heading for the next phase of the season which is surely having tough challenges as well so can they keep this momentum and will big trophy or another season while they will be chock again lets wait for the final report.