Juventus had a Stephan Lichsteiner strike early in the second half to thank for a cagey 1-0 win away to Palermo as AC Milan dominated a six-goal thriller away to Torino on Sunday.
Juventus's 12th win of the campaign took their lead to five points over Napoli ahead of their crunch visit to Inter Milan, who sit third a further two points off the pace, later Sunday.
However it was a nervous win for the champions, who despite dominating the second half -- when Palermo's Swiss defender Michel Morganella was sent off for a second bookable offence in the 75th minute -- failed to convert a number of scoring chances.
Swiss midfielder Lichsteiner settled Juve's nerves when he broke the deadlock on 50 minutes although most of the work had been done by striker Mirko Vucinic, who latched on to Andrea Pirlo's long ball and sent Lichsteiner through to beat Albanian 'keeper Samir Ujkani.
Juve were frustrated by later misses from Vucinic and defender Leonardo Bonucci, who was through on goal but ended up being shown a yellow card for simulation after he had been tackled by Ujkani, but finally managed to take all three points.
In Turin, Milan got off to the worse possible start when Argentinian Mario Santana pounced on a poor back pass from Antonio Nocerino to run down on goal and score a 28th minute opener for the hosts.
Robinho settled Milan's nerves 12 minutes later when he collected Mattia De Sciglio's pass in the area, feinted past Valerio di Cesare and beat Belgian keeper Jean-Francois Gillet with a sublime shot.
Nocerino made up for his earlier blunder when he beat Gillet in the 53rd minute to put Milan ahead and striker Giampaolo Pazzini added a third with his sixth goal of the campaign eight minutes later.
Milan were finally able to breathe easy on 76 minutes when Stephan El Shaarawy pounced to claim his 13th league goal of the season. Torino striker Rolando Bianchi scored a late consolation for the Granate.
Pescara, meanwhile, moved off the bottom of the table thanks to a 2-0 home win over fellow strugglers Genoa.
The Serie A newcomers' fourth win of the campaign puts them on 14 points, three ahead of new basement side Siena whose 3-1 defeat to Catania was their seventh of the season.
Napoli can restore their two-point deficit to Juventus later however the Partenopei face a determined Inter side which can not afford to slip further behind, especially with Lazio and Roma biting at their heels at only two points adrift.
While Lazio are not in action until Monday the Biancocelesti will be expected to take some reward from their trip to Bologna.
Roma, meanwhile, cemented fifth place on Saturday thanks to a 4-2 win over Fiorentina who sit sixth, also on 29 points with Lazio and Roma.