They both must really want to win that trophy because it's not just because of prestige or achievements, but also becomes the only hope to get to the Champions League next season. Therefore, this will be a final with a tight fight because it is very likely that they will fight to the last drop of blood. This season, Tottenham have the upper hand over Man United when the two face each other, but the Europe league is obviously different to a Premier League match, so it is quite difficult to predict who will be the winner, as anything can happen.
When one team gets a red card then the match will be lopsided. However, this is more likely to happen because of the rivalry between the two English teams, and this is the final.
The whole point of winning Europa for them is to go to UCL next season, otherwise the Europa itself has no meaning for them. I mean if both finalists went to UCL next season, then I will tell you that we will see a very boring match that nobody cares about. But we are not seeing that, we are seeing two teams whose all next season depends on a single game.
When one match is that important, you will see 100% of both teams and how great they can actually be. It is not important just for the managers, it means a lot for the players too, not only they will get paid more, but also next season if they are at UCL and play better, their value will go up too. So everyone on both sides, from kit man, to best player, everyone cares about this game not because of the title, but because they will go to UCL next season.