#3 Lack of pressing and speed in the midfield
Mourinho started with Fellaini, Matic and Pogba in the midfield. None of those are known for their speed and this was a fact that would return to haunt Manchester United. West Ham easily found spaces in the midfield and there was no pressing at all in the entire game. Every time United went forward, they lacked a driving force from the midfield, someone to compliment Pogba. Because they were playing with a front two, the gap was widely exposed. United put together just 458 passes, with 85% accuracy, where as West Ham had 455 passes, with 82% accuracy.
Mourinho should have opted for a player like Fred or even Ander Herrera to bring some energy and pressing in the midfield. Both Fellaini and Matic dropped back and gave West Ham too much space and time to operate. Fellaini was typically poor, yet the Belgian continues to be selected ahead of the more talented players in the bunch. Ultimately, it was Mourinho’s mistake in the midfield selection that gave the opposition all the freedom in the middle and cost United the game.