You can of course go on with your bet on Juventus to win. It makes sense to take that risk at these odds:

1.80 is quite good.

It can be used as even a single bet instead of increasing the risk by adding a couple of more games with much smaller odds for example. Juventus have started the season really well. 2 wins, 1 draw while scoring 6 goal and conceding none. I'm starting to like Motta despite that boring Roma game.

I hope he adopts an attacking game most of the time. At least until facing a much bigger team.
The addition of an extra game keeps increasing your chances of loosing further, but fewer games gives you a little chances of loosing the game at the tail end. Roma has been of an average performance this season and obviously they aren't going to make any easy the game, Juventus too have been of a fairly good performance which I see as a good reason to place a bet on them to win a game.