"But he played against Everton from the beginning and you can analyse his performance.
"And he played against Basle, not like (Demba) Ba or (John Obi) Mikel, coming in to rescue the game, but he came on when the team was winning 1-0 and when he had specific tasks to do.
"It's part of a process with him. One thing is to play with Ramires and Oscar in the side, them closing (down) each side, and Mata as a number 10 behind a striker, to have clever assists and to have clever passes; fantastic actions because he has great talent."
"In this moment, Oscar is my No. 10 and, if somebody tells me that Oscar is not Chelsea’s best player since the beginning of the season, I’d have to disagree. These are football issues.”
When asked whether Mata must dislodge Brazil international Oscar at present, Mourinho said: “Yes.”
He added: “They can [play together], when he adapts to it. But I’m not ready to play Oscar following full-backs, because he plays in that position for the country with more talented players than anyone else in the world in that position. I want to build with Oscar as my No. 10. I want the other two players, from the side, to adapt to that reality and learn now to do things that they were not ready to do before.”