No doubt he has miles to go. One or two games is not it, he needs a full season of good performance to lay down his claim to this spot and even then we need greater competition.
But it's not the weirdest thing ever that a youngish defender is developing. Until he went to Milan he simply didn't have enough experience in men's football. 4 years on paper but it's only since the second half of last season we've put any faith in him, after an okay if not blistering spell on loan.
He still has a lot to work on in all areas for me. He needs to keep up the aggression, be more effective in the final third and cut out the silly errors where he gets beaten easily. He's quite good between the boxes, which seems weird to say for a defender but that ability is important, but you'd want him to be tidier closer to them.