And it seems the exit from Stamford Bridge is still difficult for Matic to speak about.
"I was very happy at Chelsea, but I thought it was the right moment to change club," Matic told Football Beyond Borders.
"There were reasons which are hard for me to say now. I will never forget my time there, but I'm a Manchester United player now."
Speaking about Mourinho, Matic added: "It depends. If you win, he's the best guy ever. But if you lose, you're hiding from him at the training ground. But he's an amazing coach."