With this result, the "Vecchia Signora" with 53 points in his 6 starts of the Lombards, comfortable leader.
Naples is in its sixth defeat in eight games.
The only goal in a very disputed first time, was somewhat fortunate, since the shooting Marchisio could have stayed in the hands of Argentine goalkeeper Nicolas Navarro, but the midfielder Manuele Blasi touched the ball inadvertently and disconcerted andalusia guardavallas (44 ).
The second half was played at a slower pace, but there were times for both the marker and did not move. Even the Argentinian Ezequiel Lavezzi scored a goal that was nullified by off-side of Fabio Cannavaro and defense on the final.
Before, this Saturday, with a doublet of Argentine Mauro Zarate (36, 81), Lazio (7) defeated Bologna (17th) 2-0.
The Italian team have suffered a black weeks in European competitions.
In the last two seasons, the Inter-Roma is considered the major shock of the "calcium", but things have changed since the whole of the capital, runner today is only sixth in the table and now has 16 points less than the Champion Inter.
But it was still important to the game at the stadium in San Siro for Inter. Five days after his tie as host of Manchester United (0-0) hopes to keep pace at the top of Serie A.
The AS Roma, which can be considered fortunate not to have lost by a more bulky marker to Arsenal in London (1-0) will seek revenge from the first round, when he was crushed by 4-0. This is closer to its goal of fourth place.
But the most disappointing team of the week was undoubtedly the AC Milan. UEFA was his great goal and it was not before the end of the sixteenth of Werder Bremen (1-1, 2-2) to tie left at home on Thursday when he was winning 2-0.
Distance in the classification, also eliminated Cup in Italy, and can only aspire to the second installment of the series, which ranks directly for the next Champions League. On Sunday he travels to Genoa to measure the Sampdoria (14th), another team eliminated from the UEFA Cup on Thursday.
Just behind, Fiorentina (4th) and Genoa (5th), who also aspire to a place in Champions, visit two teams from the bottom of the table, Reggina (20th and last) and Siena (15th), respectively.