The result means Napoli have drawn their past four matches and remain six points behind of Juve with 11 games to play.
“We deserved all three points,” Mazzarri told Sky Sports Italia.
“I’m content with the way my team played, especially in the second half, which was not easy against such a strong side. It’s a shame for the result, as in the second half I thought Dzemaili’s effort was going in.
“We created a few more scoring opportunities than Juventus. We are doing something phenomenal here and will try to continue until the end.
“We keep dropping points and should’ve won against Sampdoria. But we’re unlucky at the moment. The proof is Dzemaili’s chance, which seemed impossible to miss.”