The highly-coveted Argentina international joined United this week in a record £59.7million deal from Real Madrid.
The 26-year-old has been handed the club's famous number seven shirt and his arrival has the potential to excite fans after a poor start to the season.
Van Gaal, however, has warned he cannot be expected to transform fortunes immediately.
Van Gaal, speaking at a press conference to unveil Di Maria, said: "I am very pleased that we can have such a class player in our squad but you have many class players.
"For me it is also important that he is a team player and that is what I am liking in Di Maria - not only class, and that he can accelerate the game for us, but that he can also play in the interests of the team.
Questions have been asked of Van Gaal's tactics, notably his 3-5-2 formation, and consequently where Di Maria would fit into that.
Van Gaal said: "I only buy players that can improve our philosophy so I have spoken already about his way of playing in the interests of the team.
"He can accelerate our play and our style of play but he fits in our philosophy.
"But what he can do more than fit in our philosophy, is I can change the system for him and maybe I shall do that in the future, like I have already done against Swansea City.
"He played at Real Madrid not only as a wide wing player but also in midfield so that is also a reason why we are convinced he shall succeed."
Di Maria himself is happy to fit in wherever Van Gaal wishes to deploy him.
Di Maria, man of the match in last season's Champions League final, said: "It depends on the manager and where he wants to play me.
"I come here to work for the team and I am prepared to play in any position he wants to. I just want to help the club become successful again."
Di Maria is well aware of the significance of United's number seven, a shirt worn with distinction in the past by the likes of George Best, Steve Coppell, Bryan Robson, Eric Cantona, David Beckham and Cristiano Ronaldo.