He looked like a different player from the guy who did very well at the Coppa America
Confidence is a weird thing, and for whatever reason he seems terrified when he puts on a Juventus shirt. He's not a worthless player, but he might as well be unless someone can sort his head out.
That has happened to many a player of time, and will many more. Some just can't play in big clubs, or certain clubs, they struggle and then it becomes a mental block. Every time he made a mistake he got dog's abuse, and he didn't do himself any favours.
It doesn't matter what he does for Chile, he can roflstomp over Brazil, Argentina and Uruguay every game, but it's nothing to do with or comparable to Juventus. For Chile he has no mental issues and knows exactly what his role is and where his teammates will be.
Good time player extraordinaire.