Milan, Feb 18 : Napoli missed the chance to cut Juventus' lead to two points as it was held to a 0-0 draw at home by Sampdoria in Serie A on Sunday.
Inter Milan had an even worse night and its poor run continued as it was humiliated 4-1 at Fiorentina, with Adem Ljajic and Stevan Jovetic both scoring twice for the Viola.
"It is a missed opportunity, but the championship isn't over," Napoli captain Paolo Cannavaro said.
"The whistles at the end were only because the fans are disappointed, that's for sure. We're also disappointed, especially that we couldn't play on a pitch that is worthy of Napoli. We did a miracle to get to today with all these points, playing on this pitch all year.
"Sampdoria came here to get a point. They succeeded with eight men behind the ball. But that is fair enough for their situation. We tried to get a goal bit it was difficult. We worked a lot, but unfortunately when you play against a team that is closed up, it's not easy."
Napoli confirmed after the match that the pitch -- which was cutting up badly -- will be completely re-laid during the week.
The result capped a miserable week for Walter Mazzarri's team following its 3-0 loss at home to Viktoria Plzen in the Europa League on Thursday.
Napoli remains second, four points behind Juventus. It could find itself just five points ahead of Inter Milan if the Nerazzurri beat Fiorentina later.
Sampdoria had lost on its past four visits to Napoli, without scoring a goal, and has not won at the San Paolo since the 1997-98 season.
However, it was Samp which had the better of the chances in the first half. Napoli goalkeeper Morgan De Sanctis was at full stretch to palm Gianluca Sansone's effort around his left post.
From the resulting corner, Samp went even closer and Valon Behrami had to head Andrea Costa's effort off the line. De Sanctis, who had mistimed his intervention, redeemed himself by saving the follow up.
Sansone went close again just before halftime with an angled drive which De Sanctis managed to parry.
Behrami again saved Napoli just after the break with a well-timed tackle, just as Mauro Icardi was about to shoot.
Mazzarri changed things around with a double substitution on the hour mark, bringing on Goran Pandev and Juan Camilo Zuniga, and Napoli began to lay seige to the Samp goal.
Marek Hamsik went closest when his effort crashed off the right hand post in the 74th minute and ricocheted back into the grateful arms of Sampdoria goalkeeper Sergio Romero.
Cannavaro could also have broken the deadlock with a rising effort which brushed the top of the crossbar.
Edinson Cavani went agonizingly close at the end when he toe poked an effort just wide from close range.
Inter Milan remains seven points behind Napoli after its first loss to Fiorentina since 2006. Andrea Strammaccioni's team has now only won twice in its past nine league matches.
Fiorentina dominated from start to finish and took the lead when Jovetic nodded on Manuel Pasqual cross for Ljajic to head home in the 13th minute.
Jovetic doubled his side's advantage 20 minutes later, curling a stunning strike into the top right corner, and he scored his second of the game following more poor defending by Inter after the break.
Inter failed to clear the ball and a delightful backheeled flick from Alberto Aquilani sent Jovetic clean through.
Ljajic grabbed his second of the night in the 65th. Borja Valero slotted the ball across to him and he curled into the top right corner.
Antonio Cassano grabbed a consolation for Inter with an unstoppable 30-yard rocket into the bottom left corner.
At the other end of the table, Genoa continued its revival under Davide Ballardini with a 1-0 win over Udinese.
It took the lead in the 33rd minute when Udinese goalkeeper Daniele Padelli flapped woefully at a corner and Juraj Kucka headed in.
Under Luigi Del Neri, Genoa won only two of 13 games, losing nine. It hasn't lost since Del Neri was replaced by Ballardini, drawing against Juventus and Parma and beating Lazio.
Genoa is now four points above 18th-placed Pescara which lost 2-0 at home to fellow struggler Cagliari.
Marco Sau scored both goals for Cagliari in the second half. Pescara's Vladimir Weiss -- who had earlier hit the post -- was shown a red card in stoppage time for a bad tackle on Victor Ibarbo.
Bologna remains five points above the drop zone after it lost 1-0 at Catania.
Sergio Almiron headed in Francesco Lodi's corner in the 42nd minute, moments after Gonzalo Bergessio's diving header had crashed off the base of the upright.
Bologna had won its past four matches against Catania, without conceding a goal.
Elsewhere, Torino beat Atalanta 2-1.
Torino dominated and took a deserved lead three minutes from halftime when Alessio Cerci beat the offside trap, racing down the right flank before cutting inside and firing a low, diagonal shot into the far corner.
Atalanta leveled after Torino goalkeeper Jean-Francois Gillet brought down Marko Livaja. German Denis' penalty squirmed under the body of Gillet, who had guessed the right way.
Valter Birsa sidefooted home Matteo Darmian's cross for the winner three minutes from time.