I'm going to hold off a little on comparisons to pre-injury Ronaldo and Del Piero. He looked good in preseason friendlies, it was clear talent, potential, and intelligence was there, and crazy enough, he looked far better against Chievo. To see the kind of improvement he has shown from just a few preseason matches to his first competitive match for Juve is really quite impressive. He clearly has the intelligence to make the most of his talent. But... Ronaldo, Del Piero, etc... he's got a long road to get there, littered with minefields.
I actually didn't think he lost possession all that often today. Actually, very infrequently. His positioning was a little off at times in his role as a forward, and there were spaces he should have been in at times so as to allow for better interplay with Tevez, they bunched up too tight at times, but possession, he was very strong with it, and had a brilliant first touch, and made almost no stupid passes.
Regardless of what happens with his career, that was a brilliant debut.