Manchester United brought Anthony Martial on against Arsenal because Ole Gunnar Solskjaer wanted to try and get Paul Pogba to 'dictate the play more'.
United struggled for creativity in their goalless draw against Mikel Arteta's side on Saturday evening with Pogba struggling to impact the game from the left-wing role that he started the game in.
The Frenchman was moved into the centre of midfield just before half-time when the ill Scott McTominay made way for Martial.
Ole Gunnar Solskjaer elected to replace McTominay with the French forward rather than a similar midfielder - and speaking after the match he explained why he made that decision.
"I felt we had the upper hand but didn't get Paul [Pogba] in the game the first half an hour," Solskjaer told Sky Sports. "We wanted him to get on the ball more and Anthony [Martial] to drive at them - and he created a good chance for Edinson in the second-half. We wanted Paul to dictate the play more."
Scotland international McTominay was replaced just before the half-time break after suffering from an upset stomach.
The 24-year-old was treated at the side of the pitch but was in clear discomfort after he had initially attempted to continue playing having been administered medicine.
On McTomina's illness, Solskjaer added: "Maybe the food in the hotel or whatever it was. He struggled so we had to take him off."
