It happened that things went the way of UTD because of that red card that wasn't even necessary in the first place, yes it was a penalty but how did it become a straight red card? This is another reason why I hate the use of var in some decisions, it shows that they are not working according to what they are reviewing. Wanted to see a very tough game where both teams would battle it out and not like this one man down, is frustrating. Since a draw could not happen here maybe Manchester United would try to play a draw the return leg since they are ahead of that encounter. I believe Athletic Bilbao will definitely come out to play without minding the situation at hand after all they already lost the game but if they eventually get like 2-3 goals then the contest will be heated and Man UTD will be under pressure which we all know they are not good at enduring, all the same...a good win for the Red Devils.
Hujlund was goal bound before being pulled back by Vivian. So the ref made the right call, it was a red card and a penalty according to the rules. 
Lyon with a red card played well and took the lead against United while Bilbao was demoralized and it was as if they were wishing for the match to come to an end. At this point, it's okay to say United are already in the final because I don't see how Bilbao can overturn 3 goals deficit at OT.
This game is a very crucial game and the ref should have only given the penalty and maybe a yellow card not a red, see how messy the outcome of the game was, it killed the morela of the host team which wasn't suppose to be at least a yellow card. If Manchester United was too good they would have gotten more than the 3 goals in that encounter but I feel the return leg will be different from what we witness. The Lyon game I don't want to say but that red card call was right to me but this very one I don't agree to it, the Red Devils may have their way but I believe Athletic Bilbao will bounce back. They were frustrated and if not for the control of the players it would have resulted to something different but that 3 goals will mount enough pressure on Amorim's men next week.