Van Gaal is looking to put the dismal David Moyes era behind United having taken over this summer, fresh from taking the Netherlands to the semi-finals of the World Cup. After the mid-season injury to midfielder Kevin Strootman, van Gaal switched from his usual 4-3-3 formation, and gambled on a 3-4-1-2 system - a system which his team had barely even tested ahead of the tournament.
However, it clearly worked. Van Gaal's side conjured up one of the most shocking scorelines in recent World Cup history, sweeping 2010 champions Spain aside in a stunning 5-1 win. Further impressive results against Australia, Chile and Mexico followed, though the two displays against Costa Rica and Argentina left a lot to be desired.
Now, van Gaal looks set to try and implement that same system with United. The 3-4-1-2 system was used by United in their recent pre-season friendly against LA Galaxy - a game which United won 7-0. Playmaker Mata played in 'the Wesley Sneijder' role behind the front man, and says that it's his perfect role.
"It can be very dangerous for the opponent. It is difficult for them to play against us in this formation," said Mata. "If I play behind the two strikers it's a good position -- I can look for the ball, I can try to assist or score, so I will try my best. I will try to score as much as I can and try to help the team from that position. If I have to play on the wing I will try my best as well but I feel comfortable in this role."
The system puts some players in ideal roles; Luke Shaw and Rafael have license to get forward from wing back positions, Ander Herrera can play in his preferred central midfield role, whilst of course Mata gets the freedom to play in his usual No. 10 position.
There are of course some issues though. United only have three centre backs at their disposal and Jonny Evans, Phil Jones and Chris Smalling have absolutely no depth behind them. Using it in pre-season is a big hint that van Gaal is considering using it in the Premier League too - and with a couple more additions, it could be perfect for United.