It could be that this is a strategy implemented by Manchester United to save the stamina of their attackers in the match against Liverpool in the FA Cup quarter-finals, that the match could break everyone's predictions in the match, we will never know Man United's game, maybe they will win the match or not. even knocking Liverpool out, the world of football is a surprising thing for fans, so in my opinion this is Man United's strategy in maintaining the stamina of its players to win this season's title in the FA Cup.
Manchester United have the most difficult opponent in the quarter-finals of the FA Cup, in fact, City would not be an easier opponent, but this does not change the essence, most likely everything will end for Manchester United at this stage. I am of the opinion that Klopp and his team will want to win everything they can this season and they are moving towards this goal quite well, but even the match with Nottingham for Manchester United was very difficult, and they were able to score only at the end of the match.
This Manchester united game against Liverpool is really going to be a very difficult match for them, because they both have the ability to beat each other, though Liverpool have had the upper hand in their encounter in recent times, but I believe that Manchester united will give a better fight as they did in their immediate past meeting.
Another thing Manchester united need to work on is their defense, because in most of their recent matches against the top teams, they are easily cutout open by the attacking players of the bigger teams, so they need to improve in that aspect, if they want to stand a chance of progressing to the next stage of the competition.