Giovanni Simeone’s late goal helped Napoli to a narrow win over Roma and saw them open up a 13-point gap at the top of Serie A.
Victor Osimhen’s volley gave Luciano Spalletti’s side an early lead but Roma levelled through Stephan El Shaarawy.
However the hosts, chasing a first Scudetto since 1990 and the days of Diego Maradona, pressed for a winner.
And Simeone’s turn away from Chris Smalling and effort into the top corner proved decisive.
Napoli now have 53 points from 20 games, with Inter Milan a distant second on 40 points after their 2-1 win at Cremonese on Saturday. Roma are sixth in the table, one point off the Champions League places.
Meanwhile, defending champions AC Milan slipped out of the top four after suffering a 5-2 thrashing at home to struggling Sassuolo.
Stefano Pioli’s side are on a four-match winless run in the Italian top flight and have conceded 12 goals in their last three matches in all competitions.
Domenico Berardi, Gregoire Defrel, Davide Frattesi, Armand Lauriente and Matheus Henrique all scored for the visitors as the Rossoneri conceded five at the San Siro for the first time in Serie A since April 1997, with Olivier Giroud and Divock Origi replying for the hosts.
“We have to react, we’re probably not going to win the title again but we have to fight to qualify for the Champions League,” Pioli told Sky Italia.
Juventus fell to a 2-0 home defeat to Monza to leave them languishing in 13th, while Lazio played out a 1-1 draw with Fiorentina to move up to third in the table.