When you guys are calm, think about how he hasn't even trained with the team for a week yet--let's give this guy a break. That's a below par defending from him on both goals but Icardi's shots were just really really good.
Nothing changed on my opinion about his 1st half, he was decent there but nonetheless a very poor 2nd half.
I do not see how training would have helped him not pass the ball directly off the pitch to Conte, allow Eder to freely run in the box by backing off him, failing to bring the ball out of defence when nobody is near him, completely switch off when marking Icardi. These are basic mistakes to do with concentration and instinct.
Maybe the occassion of making his debut for the Champions after climbing through the leagues affected him but I would not blame a lack of training with Juve for this. But I have to admit I have my doubts after seeing him do similar things when playing against us.
I would agree that training will improve his positioning which will be a plus.
At least the only way is up for him.