Juventus's problems continued as they were held to a 1-1 draw at lowly Livorno yesterday and also finished the game with 10 men following Felipe Melo's red card.
Antonio Filippini gave Livorno a first-half lead with a header but Nicola Legrottaglie equalised just before the break.
The draw means Juventus have now won only three of their last 14 matches, losing nine of those, and have yet to win under new coach Alberto Zaccheroni, who took over from Ciro Ferrara 10 days ago.
They also dropped to sixth following Palermo's 2-1 victory at home to Parma and now sit three points off a Champions League qualification place but having played a game more than Napoli.
All the talk in the build up to the game was about Zaccheroni switching to a back three, which he duly did, inserting Legrottaglie between Fabio Cannavaro and Giorgio Chiellini.
But whatever effect this was supposed to have on the team, it didn't work.
Juve looked secure in the beginning but suffered from their same old failing - that of being unable to fashion chances.
And if anything the new system created confusion and contributed to their falling behind on 26 minutes.
A cross from the right was missed by Livorno striker Cristiano Lucarelli but Luigi Vitale immediately sent the ball straight back in from the left and Filippini, the smallest player on the pitch, rose on the edge of the six yard box to head home despite the attentions of fou defenders around him, none of whom made a challenge.
Juve drew level three minutes before the break as a deep free-kick from Diego found Legrottaglie at the back post to head in off the upright.
The second half was dull with only a late shot from substitute Davide Moro, which Buffon palmed away, to note in terms of attacking action.
Melo was sent off eight minutes from time for a second bookable offence.
Brazilian Simplicio scored the winning goal three minutes from time as Palermo moved up to fifth.
The victory was no more than the Sicilian hosts deserved after Parma's Jonathan Biabiany had cancelled out Edison Cavani's opener.
After a goalless first half the game sprung to life when Cavani turned home a Fabrizio Miccoli free-kick on 62 minutes.
Parma equalised in contentious circumstances 10 minutes later when Biabiany's angled shot found the net but the hosts believed the game should have been stopped for a foul on Cavani in the build-up.
Even so, the Sicilians snatched the victory late on when Miccoli teed up Simplicio to smash a rasping shot into the top corner.
Next Fixtures
Friday: 20.45 Milan vs Udinese.
Saturday: 18.00 Roma vs Palermo; 20.45 Sampdoria vs Fiorentina.
Sunday: 15.00 Cagliari vs Bari; Catania vs Atalanta; Chievo vs Siena; Juventus vs Genoa; Livorno vs Bologna; Parma vs Lazio. 20.45 Napoli vs Inter.