The Dutchman will be unveiled to the media this afternoon.
"Van Gaal is one of the best coaches in the world," Witschge told Sky Sports. "You've seen that at the World Cup and he knows how to fix a team.
"I really think after this World Cup he has emerged with the credit he deserves. He will earn the respect from his players because they all know he has vision and he goes for it.
"He also understands football and knows how to talk about it. That is what will make him click with the players."
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