Five things we have learned about United under Van Gaal
1 At a stroke, Louis Van Gaal has found a way of accommodating Mata, Van Persie and Rooney
There will be talk about Van Gaal's three-man defence, but the most interesting tactical aspect of the 7-0 win over LA Galaxy was the use of a 3-5-2 formation, which became 5-3-2 when the opposition were in possession.
Last season Mata was always the odd man out, often without a natural home on the pitch or flung into a wide one – he seemed like an expensive luxury. The 5-3-2 means a No 10 role is now his and he seemed reinvigorated by this. "We have four No 10s, so the selection is not balanced in my eyes," Van Gaal said. "I have decided to play this system because of the quality of the players."
2 Van Gaal's technical demands are proving a leveller among the squad
The passing was fast and slick in Pasadena and we saw what a good technician Darren Fletcher is.
Ryan Giggs has described how new passing drills have left the returning World Cup players wondering why the non-World Cup contingent are suddenly better than them. "You would argue that the quality of the (World Cup players) should be a lot better (than the others), but the ones who've been doing it (longer) are better. It was the same for them when they started," he said. "Gradually they will get better the more and more they do it."
3 Some of this won't be easy for Alex Ferguson
Van Gaal is showing no compunction in sweeping away all that Ferguson built up and criticising some aspects of the Carrington training facility he considered to be part of his legacy.
At a stroke, he has done away with the four-man defence which was a Ferguson article of faith. Since Tommy Docherty went to a four-man rearguard in April 1975 when introducing a 4-2-4, it has always been there. "The other system they can play is 4-3-3 and they have played it for many years," Van Gaal reflected, brushing away the name 'Alex Ferguson' as if it had never been there.
4 Problem defence needs strengthening
The attacking set-up will help mask the defensive problems, which were in evidence early on against LA Galaxy. Goalkeeper David de Gea was twice called upon early in the game after United's offside trap was sprung.
Though Phil Jones played well at centre-back, an experienced world-class defender at the heart of the rearguard is an important requirement. There are not that many around. Though Borussia Dortmund's Mats Hummels is thought to be the prime candidate, he can lack pace. United cannot go into the season with Jones anchoring things and not expect to be punished.
5 There is a personal piece of reputation building at stake for Van Gaal
It's impossible to avoid the impression that Van Gaal is playing to the gallery a little – dramatising his rebuke to his players in training on Wednesday for not getting shots on target and looking like a captain on the bridge of a ship when the coach arrived for the match.
He is relishing the role of United saviour and even the criticism of the club's volume of commercial work feels like grandstanding. All of which is good for United. It will make the 62-year-old hungrier for success.