If Mata has the same defensive workrate and tenacity off the ball (he has definitely improved on these aspects this season) as Oscar, I doubt the latter would be the prefered choice right now given the former offers so much more offensively, and even more than the other AMs. And yet despite that, some players being given way too opportunity even if they are not playing well and some others being cast aside. And that's the issue, isn't it? Because of the preference Mourinho has on some players, those not exactly favored are being put so much under pressure that if they don't turn up for one game, they go back to the bench while the preferred ones get 1, 2, 3, 4, 5 etc games in a row to prove and play themselves into form. Moreover, those 2 games you mentioned there are like 4 games apart rather than giving a run of games to Mata like I was saying.