​Napoli leapfrogged Cagliari into eighth place in the Serie A standings, as Dries Mertens' 120th goal for Gli Azzurri proved the difference in a cagey encounter. 

It's been a difficult start for Gennaro Gattuso since taking the reins in Naples, but there had been signs of things really coming together prior to their home defeat to Lecce last Sunday.

Still, they were buoyed after following that up with a victory over high-flying ​Inter in the Coppa Italia semi-final first leg during the week, and they were keen for an elusive league clean sheet heading into this one, having shipped at least one goal in every one of Gattuso's Serie A matches so far. 

Gennaro Gattuso

The defensive focus of their game, coupled by the hosts' willingness to contain them without forcing the issue, resulted in an attritional encounter, one that was separated only by a single moment of magic from Mertens, who is now just one goal off becoming the ​Napoli's joint-record scorer - Marek Hamsik's 121 still setting the bar for now.

The Belgian moved within a goal of making history when he took a straightforward pass from Elseid Hysaj in the area, and within a flash opened his body and curled it out of the reach of Alessio Cragno into the far corner. 

They will hardly be pinching themselves as they sit in eighth-place, but the win means they are now just two points from the league's sixth European spot as they pursue Hellas Verona, who they travel to face at the beginning of March. 

It's been a quiet recovery for Gattuso's side but the same cannot be said about Cagliari. The narrow defeat means they are winless in ten in the league and sinking like a stone, dropping out of the top half for the first time since September.

Napoli face Brescia on Friday before welcoming Barcelona in the ​Champions League, while Cagliari travel to Verona looking to recover their still-realistic hopes of European football.   

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