Young was shifted to the unfamiliar role in the second half of the fixture, with van Gaal complimenting the 30-year-old on the way he applied himself to the new position.
"Ashley Young is very important, is a team player," van Gaal said.
"Not many players are actually team players. He is always thinking about the team. He can play in a lot of positions.
"For a trainer-coach, manager, it is fantastic that he is willing to do that.
"Because yesterday [Wednesday] he came in as a right full-back – he didn't play so much [before] there, I believe.
"But it starts with him, the second goal. So it was very important that he played there in the second half. I am very happy with him – he accepts his role, that's also important."