Mata was the pick of the bunch against Norwich but is apparently not good enough for Spain, who left him out of their latest squad.
But that was music to Di Matteo's ears.
"I am surprised - and I am very happy that he stays with me.
"I feel for him because he is in great form. I don't know the reasons why but we are happy as a club that he's going to be with us. We created a lot of chances, scored four and maybe could have scored more. We saw some good football again."