It's a reasonable set of points but it reflects the trap that football observers often fall into (myself included).
What you've not considered is that two teams will take to the pitch tomorrow with tactics designed to get the best out of their own players while reducing the impact of the opposition. It's not as simple to assume, for example, that Di Maria can pin back Sterling. What if Sterling has the opposite brief and Liverpool occupy the ball? The plan doesn't work. Di Maria can't do the thing you've suggested.
My point is that such a set of simple instructions doesn't reflect how a game pans out. Suggesting that United players 'occupy' key Liverpool players is presumably the approach all coaches have when playing Liverpool. Monk got this right for 45 mins on Monday. Then Rodgers re-shaped side and Swansea faded. That's because games don't remain in a static state. The other team start to do stuff to negate the other team's tactics.
This isn't an attack on you
@cyberman it's more of a general observation about fan-based perspectives.