Napoli coach Walter Mazzarri admits they lack a cutting edge after drawing 0-0 with Cagliari.

Mazzarri says their finishing must improve if they're to sustain a title challenge.

"I am happy with the way the team played in the second half, but we have got to be more clinical. We make too many mistakes," moaned the Coach.

"If we look at the sides fighting for the leadership, when they create four chances generally at least a couple go in the net."