Edinson Cavani struck a late winner at Parma as Napoli took full advantage of a slip from Juventus to close back to within three points of the Serie A pacesetters.
It appeared Napoli would have to settle for a draw at the Stadio Ennio Tardini after Paolo Cannavaro's own goal cancelled out Marek Hamsik's first-half opener.
However, Cavani had other ideas and the in-form Uruguayan raced clear five minutes from the end to decide a 2-1 victory and inflict a first home league defeat in 10 months on Parma.
With Juve's management going into meltdown after last night's 1-1 draw with Genoa, and Lazio losing ground due to a 1-0 home defeat to Chievo, Napoli are well-placed to launch an assault on top spot.
In the late game, Inter Milan were lucky to salvage a 2-2 draw at the San Siro after being run ragged by a Torino side inspired by Riccardo Meggiorini.
Cristian Chivu had given the Nerazzurri the lead from a free-kick but two goals from ex-Inter man Meggiorini soon turned the game on its head, only for Esteban Cambiasso to find the equaliser to spare the home team's blushes.
A solitary goal from Stephan El Shaarawy had already seen AC Milan climb above Fiorentina, who lost at Catania, following a 1-0 win over Atalanta.
The talented striker's clinical finish earned the visitors all three points in Bergamo, while Atalanta's bid for a first win in six games unravelled when Davide Brivio was sent off in the second half.
Inter's one-point haul means Milan could finally leapfrog their city rivals into fourth with victory over Udinese next week, should their neighbours lose at Siena.
Fiorentina found themselves down in sixth as Catania came from behind to win 2-1 and deny Vincenzo Montella any joy on his return to Sicily.
Bologna and Roma shared six goals in an entertaining 3-3 draw at the Renato Dall'Ara.
There were also six goals at the Marassi, with Mauro Icardi scoring four times as Sampdoria claimed an emphatic 6-0 victory over fellow strugglers Pescara.
Palermo, meanwhile, remain mired in a relegation battle after substitute Thiago Ribeiro salvaged a 1-1 draw for Cagliari.
Elsewhere, a solitary goal from Luis Muriel was enough for Udinese to seal a 1-0 win over basement boys Siena.
Oldham chairman Simon Corney has refused to clarify what the future holds for manager Paul Dickov despite him pulling off an FA Cup shock with a 3-2 win over Liverpool.
The Latics are 19th in League One, just a point above the relegation zone, and have had only one draw in their last eight matches.
A deserved victory over Premier League opponents does not appear to have safeguarded Dickov's short-term future and he and Corney will meet tomorrow for talks about the way forward.
"We know we have poor form in the league and things need to be changed," said Corney just minutes after Oldham booked their place in the last 16 for the first time in 19 years.
"Football changes. People are very fickle, fans are very fickle, everyone is very fickle.
"Nothing will take away from the fact I need to change things to stay change in this division.
"Let's see what happens. Nothing has been decided and I couldn't tell you any more than that.
"I just want to enjoy today and the next 24 hours and we'll get back to work tomorrow.
"My thoughts change. We know we haven't done well and it's not a surprise.
"Paul is the first one to say when you get one draw out of eight games things are going to be spoken about and things are going to happen.
"But things in football changes very quickly we know that. One big win, two bad losses can change your mind.
"If you asked 1,000 people last week if we should change the manager 999 would have said yes. Today 999 would say no.
"I'm not ashamed or embarrassed to say it is difficult."
