Ricky Alvarez was controversially sent off to leave Inter with ten men.
"I complimented my players for their performance and I am proud of them. We are growing and now must work on our style of football, which today was exceptional. We made life difficult for Napoli and forced them to only go on the counter-attack in their own stadium," said Mazzarri.
"We weren't as concentrated on the preventative marking on the counter-attack, so we need to be more ruthless. I told my men that if we always play like this, we will not lose many games."
Mazzarri did not disguise his absolute disdain for referee Paolo Tagliavento, especially with regards to the Alvarez dismissal.
"There was a series of terrible mistakes that changed the game. When we were in control and 3-2 down, Alvarez was harshly sent off. The first card was harsh too, as he tripped up. I saw far worse challenges that were worthy of a card. I think with 11 men against 11 we could've got back on level terms.
"Perhaps Tagliavento is unlucky with us, as we've had two defeats all season and both were with Tagliavento making many mistakes. The other loss was against Roma with a non-existent penalty. We're unlucky with him, it keeps happening to us. Maybe Tagliavento is just out of shape."
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