The Reds manager was given his coaching chance at Chelsea by Mourinho.
The Portuguese told Five Live: "Brendan was a young guy when he started working at Chelsea. He had lots of energy, lots of enthusiasm, very good ideas.
"He was learning but also showing his ideas, sharing things.
"I enjoyed very much working with Brendan and we keep in touch. I am not saying every day or every week, but we keep in touch a lot because it's the kind of feeling we want to keep forever.
"I want him to be a success, to keep doing things well.
"I am so happy they (he and Steve Clarke) are on top."