#4 Juan Mata
The Spaniard started the game from the right and looked lost for the opening 15 minutes. Mata rarely got on the ball and was largely isolated because United were overrun in the midfield. When Solskjaer shifted him to the false 9 role, the Spaniard found his footing and helped United get a grip on the game.
His positioning in the middle helped United nullify Watford's advantage in the middle of the park. With Pogba having an off day, Mata took responsibility and started putting together passes that helped United get back into the game. Watford had no answer for his clever movements, which caused the defense and midfield all sorts of trouble.
The Spaniard started operating in the space left open by the away side in between defense and midfield. From here, Mata threaded passes to Rashford and Martial. He brought Pogba into the game and switched play with ease. Ultimately, United rode the momentum gained from his passes to win the game.