I think it's not just the finishing that looks worse where almost all of Manchester United's positions are not performing well.
The goal happened because of a mistake in the midfield where Casimero made a mistake and the defenders also didn't try to cover the empty position before Liverpool players scored.
Superior in terms of possession of the ball is not a reference because they even had difficulty scoring goals or suppressing Liverpool's attacks.
Yeah Zirkzee already tried to score a goal, but come on, he's fighting against Becker, one of great goalkeepers in the world. It's completely different for Liverpool's strikers who fight against Onana, that's why they can score 3 goals.
Shots on target by Liverpool is 3, it means Onana saves zero in this match.

Erik Ten Hak must also give the opportunity to play to other goalkeepers because I see Onana has no instinct at all in making saves, especially in this match which conceded three goals.
He bought Bayindir for no reason, stupid Ten Hag.