The travelling United supporters chanted “attack, attack, attack” and “four-four-two, four-four-two, four-four-two” as the visitors laboured in possession and failed to create too much in the first half of Saturday’s Premier League clash at Loftus Road.
Van Gaal reverted to a diamond midfield after the break and substitutes Marouane Fellaini and James Wilson both had an impact as they scored to secure victory.
But the United boss insisted he will not revert to that system permanently, saying he will decide on the right shape depending on their opponent.
“I know in advance that when we play with four midfielders in a diamond that we create more chances, but then the balance of the team is also weak,” he said.
“And you’ve seen it because we had created chances but so had QPR.
“We have to decide every week how we have to play. And that’s the question.
“In the first half, we played like QPR wanted. We did the same thing as QPR, playing through the air, long balls, and QPR were better.
“In the second half, we changed the shape and that helped also.”
Radamel Falcao endured a disappointing afternoon in front of goal, with the striker denied three times by QPR goalkeeper Rob Green while also missing a glorious opportunity to tap in at the far post.
Van Gaal said he was pleased with the Colombian???s display but knows Falcao will be disappointed not to have got on the scoresheet.
“I think he did well,??? he said. ???[But] it’s not so important what I think, because he wants to score goals.
“And for me, I have to judge how he has played.
“Scoring goals is an important aspect of a striker I know, but for me it’s also very important if he is an attacking point, that he can play further and that with another striker we are coming into third and fourth phases of our attack.
“And I think he did well.”