Milan: Defending championS Juventus struggled again as they were held to a 1-1 draw at Parma in Serie A on Sunday.
Andrea Pirlo gave Juventus the lead with a trademark free kick early in the second half but Nicola Sansone leveled in the 78th minute to preserve Parma's unbeaten home record.
Second-place Lazio are now only three points behind Juventus after recording a controversial 2-0 win at home to Atalanta.
It is a blow for Juventus, who had an eight-point advantage at the start of the year.
Former Atalanta striker Sergio Floccari gave Lazio the lead after the ball struck his arm, and an own goal from Davide Brivio sealed the result.
Napoli are two points further back after cruising to a 3-0 win at home to Palermo. Fifth-place Fiorentina surprisingly lost 3-1 at Udinese as Antonio Di Natale scored twice.
Juventus were eager to get back to top form after a loss at home to 10-man Sampdoria last week and a narrow extra-time victory over AC Milan in the Italian Cup.
However, Parma is the only team left in Serie A yet to lose a game at home.
Parma dominated the early stages but Juventus slowly began to get into the game and Pirlo sounded a warning shot at the end of the first half with a free kick which Antonio Mirante did brilliantly to keep out.
Pirlo had scored four goals this season, all from direct free kicks, and he added to his tally when his effort was deflected off Jonathan Biabiany in the wall and completely wrong-footed Mirante.
Parma levelled on the counter attack when Gabriel Paletta sent a great ball throught to Sansone who raced clear of Martin Caceres before slotting it past Gianluigi Buffon.
In Rome, Floccari broke the stalemate in the 67th minute. Stefan Radu's cross was bundled onto the crossbar and the rebound hit the striker's arm before he fired it home from a couple of yards out.
The Atalanta players were furious and surrounded the referee but the goal stood.
Lazio doubled their lead when Brivio headed Stefano Mauri's cross into his own net.
Atalanta ended the match with 10 men as Carlos Carmona was sent off after picking up a second yellow card.
Napoli cruised past Palermo 3-0 with goals from Christian Maggio, Gokhan Inler and substitute Lorenzo Insigne for their third consecutive victory.
Insigne's younger brother Roberto also came off the bench, to make his Serie A debut.
Edgar Barreto hit the bar for Palermo with a free kick.
Udinese goalkeeper Zeljko Brkic had a miserable day as his team recorded a second win on the trot, following its 3-0 win over Inter Milan.
His own goal gave Fiorentina the lead. Gonzalo Rodriguez's header crashed off the crossbar and in off the goalkeeper's head.
Brkic was then forced off with a broken finger.
Udinese leveled through a penalty by Di Natale after Borja Valero was adjudged to have fouled Maurizio Domizzi.
The Udinese captain doubled his tally in the second half before, seconds later, a howler from Fiorentina goalkeeper Neto saw Luis Muriel extend his side's lead.
Roma also lost, going down 1-0 at Catania.
Alejandro Gomez scored the only goal of the game on the hour mark.
Elsewhere, Cagliari recorded their first league victory since October as they came from behind to beat fellow relegation candidate Genoa 3-1.
Marco Sau and Daniele Conti grabbed the goals for Cagliari after Eros Pisano had headed Genoa into the lead with his first Serie A goal.
Genoa's Felipe Seymour was shown a straight red card seven minutes from time.
Earlier, Torino beat fellow struggler Siena 3-2, although the bottom club came agonizingly close to pulling off a thrilling comeback.
Former Torino midfielder Alessandro Rosina blasted a penalty wide a minute from time after Matteo Brighi had fouled Francesco Della Rocca.
Brighi had given Torino the lead in the fifth minute but Reginaldo bundled in the equalizer shortly after the half hour.
However, Rolando Bianchi and Alessio Cerci put Torino 3-1 up before halftime.
Siena was back in the game in the 75th when Reginaldo backheeled a cross for Michele Paolucci to fire home.