The 40-year old, who was on Wednesday appointed as Boro’s new boss, worked with Chelsea’s Mourinho at Real Madrid and said it was an honour to work with such a remarkable person.
"Working with him every day, every minute, is the best," Karanka told Sky Sports.
"He is the best coach and an amazing person who is always helping you and you can learn so much from him, every day.
"I was speaking with him every day in the last month, he is a good friend with me and he is very happy for me. He told me that it was a great club, he said it is a good opportunity."
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