Napoli coach Rafa Benitez was bitterly disappointed after his side threw a two-goal lead against Cagliari.
The Partenopei started the game brightly with Gonzalo Higuain giving his side an early lead before Gokhan Inler added a second on the 30th minute but more mistakes in the Napoli defence first allowed Zeman's side to get back in the game and eventually restore parity in the second half.
Jonathan De Guzman's 62nd-minute goal brought smiles back on the faces of the Napoli fans but the joy was cut short when Diego Farias scored his second of the game.
"We had the match in our hands but we gifted Cagliari the draw," Benitez said after the game.
"We lost intensity after taking a two goal lead, we could have scored more but defensively we didn't do as well as we did in our last 3-4 games.
"Cagliari play nice football, always on the attack but we did well to take a comfortable lead.
"It's disappointing to concede after working so hard to score goals. We gifted them the draw and this is a concern. The approach was right in the first part of the game and we should have insisted with that mentality.
"I repeat, I'm angry because the game was in our hands and we gave it away. But we have to keep our focus and look forward.
"We will together understand the mistakes we made today, trying to eliminate them from our game.
"But I also saw positive things that should not be ignored in our performance.
