United to play 3-4-3, says Van Gaal
United kicked off their pre-season tour of the United States with a 7-0 rout of the Los Angeles Galaxy at the Rose Bowl Stadium on Wednesday.
Wayne Rooney, debutant Reece James and substitute Ashley Young netted two goals apiece, while Danny Welbeck was also on target.
However, United's formation arguably attracted the most attention as Van Gaal opted to utilise three central defenders - Jonny Evans, Phil Jones and Chris Smalling - as he did during the Netherlands' recent World Cup campaign.
New recruit Luke Shaw and Ecuador international Antonio Valencia operated as wing-backs in a sign of things to come at Old Trafford, according to Van Gaal.
"We introduced a new system that we have only played two times on the training pitch 11 v 11," the Dutchman told reporters post-game.
"But the boys are willing to pick up the information. It is fantastic how they have performed.
"Last week, 10 players who played tonight were not even in our training complex.
"When you want to change a system, you must start at once. We don't have time to prepare for other things.
"The other system they can play is 4-3-3 and they have played it for many years.
"I can change back if the system doesn't work. With the quality of the players we have, I can play 4-3-3 with three strikers on the bench, but I want to play with two strikers."
Van Gaal believes United's performance against the Galaxy will help instil confidence in his players as they attempt to become more familiar with the new system.
"It was not just the goals, but the beautiful attacks," said the 62-year-old.
"I never go back, I always want to see the future.
"When I see my team playing a new system, it is better to win 7-0 than to lose because the players will then doubt the system.
"But now I don't have that problem."
However, Van Gaal also acknowledged his side lacked balance with the likes of Juan Mata and Shinji Kagawa possessing similar characteristics.
"We have four No. 10s, so the selection is not balanced in my eyes," he said.
"I have decided to play this system because of the quality of the players.
"But if we lose, I can change back to another system."