The Sunderland head coach, who celebrated his 68th birthday on Sunday, played with 64-year-old Van Gaal at Sparta Rotterdam but has locked horns with him throughout his lengthy managerial career, and more often than not come out on the right end of the result having lost just once in 10 meetings.
However, he has the utmost respect for his fellow former Holland manager as he attempts to get the better of him once again.
Advocaat said: "He's one of the best coaches in the world, no doubt about that
He has worked at the highest levels in Europe.
"He is a manager who does not just look for the easy way, he is always looking for the most difficult way
If you see his prize list, it is unbelievable, so I rate him very highly."
The pair forged their relationship in the Sparta team during the early 1980s with the older man nursing Van Gaal through.
Advocaat said with a smile: "He played with me at Sparta for two years
You heard what I am saying ..
he played with me!
"He was a different player to me
I would get the ball and give it to him
He had the eyes - and so did I later - but in the beginning, I gave it to him because he was a good player.
"He was not the quickest
But he is a good guy
If you know him well, he is a good guy."
Sunderland will head for Old Trafford sitting at the foot of the table and without a win in their opening six league games to meet a United side sitting in second place.
Advocaat has only once before come across the Red Devils in a competitive match during his illustrious managerial career, leading Russian side Zenit St Petersburg to a 2-1 victory in the 2008 European Super Cup in Monaco, before which the former Rangers boss shared a few stories with former Rangers striker Sir Alex Ferguson.
He said: "I had a great conversation before the game with Ferguson
He wasn't laughing after the game because I beat him."
Sunderland will have central defender Younes Kaboul back from suspension, but midfielder Jack Rodwell and striker Jermain Defoe are doubts with ankle and hamstring injuries respectively.
Source : PA
Source: PA