Inter are ahead of Napoli by only 4 points, but you need to take into account that Inter played one game less, so they can potentially further increase their lead over Napoli.
Inter Milan have one more match but it does not mean 3 more points will be credited to their pocket. They have to play and fight and they might lose point. So let's assume Inter Milan have 3 points, they will have 7 points more than Napoli. In my opinion, Napoli still have chance with 7 point difference. 7 points mean just 2 or 3 bad matches and things will change a lot.
Juventus are gradually gaining form, but they need to strengthen the attack line in order to count on something more. I didn't like how they played against Milan because the Juventus attack didn't create any really dangerous moments.
Juventus will have better attacking power with Vlahovic from Fiorentina. His total goal in this season is about half of total goals Juventus have so far. This transfer might make more hate from Fiorentina fans against Juventus. They were angry when Roberto Baggio left them and moved to Juventus. Now, Vlahovic, let's see how they will react after this transfer.