Manchester United's job is easier now after Arsenal have been eliminated in the Europa League. But by saying easier I don't mean they will be very comfortable. There are still challenging teams in the tournament now. Besides if they get past Sevilla their opponent will be one of Sporting and Juventus. I assume it would be Juventus if they play carefully against Sporting.
Manchester United should be able to eliminate this Sevilla as well. Sevilla are far away from even their performance in the previous season.
Manchester united have gotten some relief in the Europa League after arsenal was defeated by sporting. I know arsenal in the Europa League look intimidating to Manchester based on the performance in the English Premier league. Now there competitors in the league is Juventus and Sporting.