The Dutchman had the Blues boss on his coaching staff at Barcelona and revealed he put him in charge of cup matches at Camp Nou in recognition of his talentManchester United manager Louis van Gaal has praised Chelsea boss Jose Mourinho ahead of Sunday's clash between the two sides, stating he would like his team to play like his former protege's.
Mourinho worked as a coach under Van Gaal at Barcelona in the 1990s, and had earlier thanked the Dutchman for his help in the early days of his career.
But Van Gaal says he had already recognised the potential of the Portuguese, which is why he gave him the responsibility of taking charge of Catalunya Cup matches.
"It is not such a great tactical battle because his team plays how I want to play with my team, so I don't think there are secrets any more," Van Gaal told a press conference on Friday.
"He has said that [he learned a lot at Barcelona] and it's remarkable because not many people talk about that.
"He says it not only about Louis van Gaal but Bobby Robson. I appreciate it but you always do it by yourself.
"I was also an assistant coach and my eyes were also opened and it’s good that his eyes were open when he was my assistant, but you do it by yourself.
"I know Jose already has talent because I let him do cup matches instead of my other coaches. He's a wonderful coach and to see him as a coach winning trophies in other countries is fantastic."
When asked what had impressed him most about Mourinho, Van Gaal replied: "That you can never imagine that he is a very modest and emotional human being - and I like that.
"But it's a surprise, no? He's one of the best coaches in the world."