League leader Napoli moved provisionally five points clear with a 4-2 win at 10-man Sampdoria on Sunday, ahead of Juventus' match against Roma as Inter Milan's woes continued.
Serie A's top goalscorer Gonzalo Higuain was on target again to set Napoli on the way. Lorenzo Insigne netted a penalty before goals from Marek Hamsik and Dries Mertens sealed the result.
Napoli moved five points clear of Juventus, which is seeking an 11th successive league win. Inter is now six points off the pace after a last-minute equalizer by 10-man Carpi held it to a 1-1 draw.
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Fiorentina is above Inter on goal difference after Josip Ilicic and Gonzalo Rodriguez secured a 2-0 win over Torino.
Elsewhere, Sassuolo lost 2-0 against Bologna while Lazio came from behind to beat Chievo Verona 4-1 in a match that saw both sides finish with 10 men and the visitors miss a penalty.
Palermo also won 4-1, against Udinese, and Hellas Verona drew 1-1 against Genoa.
Higuain had been in good formwith 20 goals in as many league matches this season and, although he missed an early chance, he got Napoli off to the perfect start in the ninth minute, pouncing onto Edgar Barreto's woeful backpass and firing into the bottom left corner.
Matters went from bad to worse for Barreto in the 17th minute when he barged over Raul Albiol and Insigne converted the resulting penalty.
Joaquin Correa got Sampdoria back into the game on the stroke of halftime but the home side went down to 10 men shortly before the hour mark when Mattia Cassani was sent off for a second booking.
Napoli made the most of the man advantage as Hamsik immediately scored after a slalom run between two defenders.
Samp got back into the match again in the 73rd with a glancing header from an Eder corner, but substitute Mertens sealed the result 10 minutes from time.
Inter was eager to get back to winning ways in the league following a defeat and a draw, which had seen it fall from top spot.
Rodrigo Palacio broke the deadlock shortly before halftime, tapping into an empty net after Ivan Perisic's shot was deflected into his path. And Inter appeared assured of the three points when Lorenzo Pasciuti was sent off following a second yellow card, seven minutes from time.
But Kevin Lasagna stunned the San Siro crowd with a stoppage-time leveller after dodging the offside trap to run onto Raffaele Bianco's through ball.