However, Gallagher has insisted that despite Baggies head coach Alan Pardew suggesting that a spot kick should have been given, he feels that Anthony Taylor made the correct decision by not giving a foul.
Gallagher told Sky Sports News: "I never even considered this to be a penalty. I was watching the game live and it shocked me when someone said earlier that it could be a penalty.
"I think the referee sees its shoulder to shoulder, sees the goalkeeper coming and it doesn't cross his mind. You see James McClean just stand up, it doesn't cross his mind."
United would go on to record a 2-1 victory at The Hawthorns.