To be honest, I don't think that's entirely true. There are a lot of articles and podcasts, where people attest, that Manchester United this season got better in pressing themselves. And that in turn, this also will help to beat the press. Another factor: actually, we are very very good against teams that have a go at us usually (Sociedad, Leipzig, City on a few occasions). So my conclusion is, that Liverpool didn't "just press us" but that they found ways to shut down Cavani, Bruno, Pogba and Shaw and bring out the worst out of the rest of the team. We should find out what it is so we can counter that next time
I learned it isn't very well manored to answer questions with counter-questions but I think, this damages your arguments more than mine.
I haven't said that something is down to luck or anything, nor am I the one to imply, that we are badly coached in this aspect. I asked you, if you agree that we struggled today due to the press. I am sure you do - so who do you think, should be responsible to make sure, that we are better prepared for game situations like this next time/match/season? Surely the manager, right?
You shouldn't be too defensive towards your manager that you become to biased to see what happens on the pitch. Today we had a problem. If you think, it was just down to bad luck and off-days from particular players, I think you aren't willing to see the full picture.