Interesting to get a first proper look at Juve's 4-2-3-1.
In the previous games Juve had inconveniently scored too early to really see how the system functioned.
But I think this game gave a good indication of what it is like and it is pretty typical of what happens when you play a system with few midfielders and lots of attackers.
You can either open the game up, and make it a battle of attack versus defence at both ends of the pitch, or you can drop off and get men behind the ball and play on the break.
The key thing in both cases is that you are forced into playing both or either of those ways by not having enough midfielders on the pitch to give you a decent chance of playing any periods of controlled possession to dictate the tempo of the game in the way that Juve have done to good effect in previous seasons.
Juve have the players that mean they will almost invariably win games that are wide open in Serie A, but Juve will almost invariably win any kind of game in Serie A.
I don't think Juve are good enough at playing an open game for that to really be a viable plan against a good team in the CL.
They may, however, be good enough at playing in the way they did in the second half against Inter against a good team in the CL.
Juve should be able to get better at playing open periods like the first half. Most of Juve's problems in that half came from Pjanic and Khedira getting wrong side of Joao Mario and that allowed Inter to start a counter-attack. I doubt Marchisio would make the same error if he played in place of one of them.