Champions Juventus kept pace with Serie A leaders Napoli on Saturday after a hard-fought 1-0 win over title-rivals AS Roma with Inter Milan suffering a second consecutive defeat.
Moroccan Medhi Benatia scored the only goal against his former club after 18 minutes in Turin.
Juventus remain one point behind leaders Napoli -- who have 45 from 18 games -- with Inter Milan five points adrift in third after losing 1-0 at Sassuolo, and Roma in fourth.
It was the first time that Roma have trailed this season away but Eusebio Di Francesco's side could not find a way back, despite almost equalising in injury time when Patrik Schick hit the crossbar.
Juventus also had chances to increase their advantage with Gonzalo Higuain wasteful and Miralem Pjanic's stoppage time effort cleared by Alisson by the tips of his fingers.
"The team could have done a lot better, maybe we were a bit inhibited, against a team like Juventus you can't afford to make mistakes," said Di Francesco as Roma -- with a game in hand -- sit seven points behind Napoli and six off Juventus.
Earlier Marek Hamsik scored his 116th goal to overtake Diego Maradona as Napoli's all-time record scorer, at the same time sealing a come-from-behind 3-2 win over Sampdoria.
"I'm proud to have overtaken a myth like Maradona. My friends gave me shin-pads with 116 on them, but my first thought was that we were winning the game after going behind twice," said the 30-year-old Slovak international.
"Today winning was very important because we also gained points on Inter even if the championship is long."
Napoli were trailing twice in the first half with Gaston Ramirez firing in a free-kick after just two minutes to catch Pepe Reina off guard.
But Allan equalised after a quarter of an hour at the San Paolo stadium only for Fabio Quagliarella to convert a penalty to restore Sampdoria's lead after 27 minutes.
Lorenzo Insigne marked his comeback from injury with a volley on 33 minutes following a Dries Mertens flicked cross.
But it was captain Hamsik who sealed the victory six minutes before the break, again off a Mertens cross, and Napoli held on despite Mario Rui's sending off.
"The important thing is that we won while suffering, as it's a victory that counts for even more, because Inter lost today as well," added Hamsik.
- Inter stalled -
Despite their remarkable start to the season, Inter have taken just a single point from their last three matches, with back-to-back losses to Udinese and Sassuolo.
Diego Falcinelli headed in the only goal after 34 minutes at the Mapei Stadium, with goalkeeper Andrea Consigli saving a penalty from leading Serie A scorer Mauro Icardi.
Luciano Spalletti's side are third but just two points ahead of Roma, who have played a game less.
"We've lost two games but I've seen good things in these games, perhaps there hasn't been the most consistency and there have been some moments which weren't the smartest," said Spalletti.
"We paid a high price for certain episodes. To become a strong team and to consolidate on what we've done, we need to get through moments like this."
Lazio, also with a game in hand, are two points off Roma after easing past Crotone 4-0.
But things have gone from bad to worse for Chinese-owned Milan who lost to direct European rivals Atalanta, who are in seventh position.
Milan's training retreat after last week's shock defeat by Verona had little effect on Gennaro Gattuso's side.
Former Milan midfielder Bryan Cristante opened after a Gianluigi Donnarumma error in the first half with Josip Ilicic finishing off the second on 71 minutes.
Sparks should fly on Wednesday with AC Milan and Inter Milan meeting in an Italian Cup quarter-final derby clash in the San Siro.