Ralf Rangnick believes Manchester United gained control of their FA Cup win over Aston Villa when Donny van de Beek came on.
Van de Beek replaced Edinson Cavani in the 72nd minute and United switched to a midfield diamond to counter Aston Villa's dominance in midfield.
In the final ten minutes, Rangnick introduced Anthony Elanga and Jesse Lingard for Marcus Rashford and Bruno Fernandes to freshen up a blunt attack and United saw out a tight contest relatively comfortably.
"The game against Villa today confirmed, with a minimum three central midfielders, we had problems in times of the game to control the centre of the pitch," Rangnick explained. "From the very moment when we changed to a diamond in the last 20 minutes, when Donny came on, from then on we controlled the game, we had our counter-attack situations.
"Unfortunately, we didn't take the right decisions in the final third, so if we had done that we could and should have scored the second goal. But it's not so easy to control the centre of the pitch and at the same time have our wing players involved and play with at least one central striker.
"For us, on the bench, that was a difficult job to find out how we could do that. In the end, we decided to take off Edi and had a diamond in midfield and have two fast wingers as the only strikers on the pitch.
"It's all about balance. Offensive and defensive balance and we have players whose strengths are up front when we are in possession of the ball but in order to control and dominate the game you have to have possession of the ball, and make the best out of that possession.
"You saw the way we prepared the goal was brilliant; we kept control around the box, we changed sides, a brilliant cross and fantastic header by Scotty.
"As a coach, I am always somebody who likes to have control and wants more control. It's a question of balance and we still need to improve in those moments."
