I can see why it shows him with that kind of score, as mentioned above its likely based on loads of meaningless stats plus being a goal scorer also likely to boost it up a bit, I don't think he had a particularly great game and was left un-involved for long spells, but what he did I cant really remember him doing anything wrong so thats probably why his score is so high
on a side not Ozil getting 9.76 essentially means he had a near on perfect game, which just seems ridiculous to me, it would practically mean completing every pass, and winning every tackle/header he went in for and playing a part in all the goals, just seems highly unlikely that all of that happened