Louis van Gaal hailed a “fantastic” performance after Manchester United hammered LA Galaxy 7-0 in his inaugural match as manager.

Two goals each from Wayne Rooney, Ashley Young and the debutant Reece James, plus Danny Welbeck’s opener, returned an emphatic victory in United’s opening game of their summer tour of the US.

Van Gaal, who made nine changes at half-time, said: “The result always matters. With such a result you get confidence, and confidence in a new system. We introduced a new system and played two times on the training pitch 11 v 11. It is not so much, but the boys are willing to pick up the information.

“It is fantastic how they have performed today. Last week, 10 players who played tonight were not even in our training complex. But when you see us train, you can expect something but not 7-0. It was a surprise, but they were also beautiful goals.”

Although United were understandably rusty Van Gaal was encouraged by his new team’s play, which at times was quick-paced and fluid, in what was a new 5-3-2 formation. He said: “It was not just the goals, but the beautiful attacks. 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 want to play with two strikers.

“We have four No10s, so the selection is not balanced in my eyes. 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.”

United now fly to Denver where they play Roma on Saturday in the opening match of the International Champions Cup. “I am never afraid and I am thinking of my team, not Roma or other teams. The qualities of my team mean they will also try to perform well.”

Van Gaal claimed the squad are not suffering from a lack of confidence despite finishing seventh last season. “Not a problem. I never go back, I always want to see the future,” he said.

“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.”

United’s new £29m signing Ander Herrera said: “We are happy with the result but let’s not forget this is a friendly and we still have many things to improve on. Our coach is a very demanding coach, he always looks for only perfection and for that reason he is ideal for a club that always looks to achieve the greatest things, he won’t let us sit back and relax or sit back, we still have a lot to prove.”

Herrera said that now he was at United he hoped to emulate his hero Eric Cantona. “I liked his character, he was a winner and always worked hard, he never lost one ball and was always thinking about the victory.

“This group of players has those same characteristics. We always want to win, we want to play well for the Man United supporters and Eric Cantona had those characteristics. Of course, he had personality too.”