Because Liverpool have record in Champions League more than premier league, they always meet Real Madrid that also have record in Champions League and the meeting is just so constant now and like the four times that they have meet now, they haven't been able to beat Real Madrid in any of the matches and I doubt that they can beat Real Madrid because they didn't have the caliber of player that can do that for them and they are currently not in good form. Liverpool recently winning two matches in premier league doesn't mean that they are back in form, they aren't back, they are still trying, not even against Real Madrid they can say that they are back, Real Madrid seems know how to beat them.
The real cause of Liverpool's loss is from the midfield, the midfielders aren't playing like the midfielders that used to play last season, last two seasons that always compete with Manchester City, Liverpool suppose to get midfielders in the January transfer that just ended but they didn't, and as they didn't, the weak ones that aren't in form can't do more than their capacity and as the midfield is not good, it affected the defense line, of which that defense line isn't even complete because Geo Gomez place is not central defense, his place is ring wing that Trent Alexander-Arnold plays and it's not possible for him to do what he's not good at.
Trent Alexander-Arnold didn't put all his best in the match because he's scared of the yellow card that won't make him play the second leg and as it seems, there is nothing for them to play in second leg, the three goals debt can't be that easy to pay back at Santiago Benabiu in the second leg, I'll just assume that Liverpool is not of UEFA Champions League this season, all that they need to place their focus on is premier league and run maybe they can meet up to Top 4, anything is possible in football, in premier league, not the Champions League that they've already concede 3 goals.
139.378 SRY