Napoli coach Walter Mazzarri is wary of this weekend's opponents Inter Milan.

Mazzarri has been impressed by Inter's defensive setup.

"Inter are doing some great things with their three-man defence," said Mazzarri who has used the system for some time.

"They have players like Esteban Cambiasso, Diego Milito and everyone else who have been giving them something extra in recent times."