#3 Close attention to Jorginho and Hazard
Solskjaer knew that Jorginho and Hazard were the key ingredients to Sarri ball's effectiveness. As such, he made a few subtle tweaks to his formation to ensure that both of Chelsea's main men had little effect in the first half.
For starters, he kept Mata close to Jorginho. The Spaniard pressed the Italian and ensured that he did not have too much time on the ball. Whenever Jorginho ventured closer to the United box, he had either of Matic or Herrera for a company. As such, the Italian never had much impact on the entire game.
On the other hand, the Norwegian instructed Ander Herrera to help out Young every time Hazard came to town. As such, even though the Belgian saw plenty of the ball, he was almost always crowded out. Young and Herrera double teamed up against the Chelsea No. 10 and rarely let him enter the United box with the ball.
By stopping both Hazard and Jorginho, United successfully cut off Chelsea's threat on the night.