The Europa League is the only way for Manchester United to seal a place in the Champions League if they are able to become champions, but if you look at their current performance then of course everyone will be very pessimistic because the opponent they face in the semi-finals is Atletico Bilbao. When compared to United then Bilbao is clearly better in terms of overall statistics. However, hope for the Red Devils is still open, Amorim really must be able to take advantage of this situation in order to maintain his reputation because there is no other way to fix all the slumps that have occurred except by winning the title in this tournament.
Athletic Bilbao have the confidence of qualifying for the Champions League next season considering their position and points in the La Liga table whereas Manchester United's only hopes of qualifying for the Champions League is by winning the Europa League which will make them more serious than Athletic Bilbao, not that Athletic Bilbao don't deserve to win it but am just looking at it from the angle of the team that will be more inquisitive for a place in the Champions League.
Amorim's target is on the Europa League title and this is just the most difficult team they will face because if United reach the finals and meet Tottenham or Bodo/Glimt, United will be assured of winning it. What United need to do in this game is to fight for at least a draw then when they come to old trafford in the second leg they can now win and move straight to the final. Manchester United came to the Europa league through the FA Cup title so am seeing a kind of connection in the Europa League which will also make them qualify for the Champions League next season.