The Croatia midfielder joined Real in August from Tottenham.
He said: "I am adapting well. When I arrived I said that whatever position I was asked to play in, I would try to do it the best I could and play to my full ability, but my favourite position, where I am most comfortable and play the best, is in the centre of the pitch along with Xabi or Khedira.
"Real Madrid is the best team in the world and expectations are very high. Mourinho wants to play the way I did at Tottenham, but faster and more aggressively. I am progressing well and now I understand what the coach wants from me."