The Red Devils have come under fire for much of the season for their style of play and poor results, yet United are currently fourth in the Premier League and on course to qualify for the Champions League.
And Hasselbaink, manager of Burton, and a Netherlands international under Van Gaal, has sung his praises.
Speaking to the Daily Mail, he said: "He [Van Gaal] is mild! I’m telling you. I need to find the time to go over to Manchester and have a cup of coffee or tea with him when he is not that busy.
"He is somebody who tells you exactly what he wants, how he wants and when he wants. There are no prisoners. But he is a very loving man and a top coach, one of the best in the world.
"Of course he has come in for criticism because he is manager of one of the biggest clubs in the world, but let’s not forget, Manchester United is changing.
"I am 100 per cent he will succeed and they will play attractive football."
United, who are five points ahead of fifth-placed Liverpool, resume their pursuit of a top four finish when Aston Villa make the trip to Old Trafford on Saturday.