Milan - Second-half goals by Duvan Zapata and Marek Hamsik guided Napoli to a 2-0 win over Sassuolo and saw them close to within three points of Roma in Serie A on Monday.
The later match saw Inter Milan's revival under Roberto Mancini continue as they recorded their third successive win with a 2-1 victory at relegation-threatened Cagliari.
Napoli - who are just three points in arrears of Roma who have drawn six of their last seven games - managed to hold on despite Belgian midfielder Dries Mertens being sent off only six minutes after coming on as a substitute for a tackle from behind on Simone Missiroli.
For Napoli it was their fifth win in six matches and while the 12 point gap to leaders and defending champions Juventus might appear insurmountable the gap with Roma for the second automatic Champions League spot -- a goal of coach Rafael Benitez' -- is certainly within reach.
They could take a significant step towards that goal next week when an ailing Roma host Juventus at the Stadio Olimpico.
With Argentinian striker Gonzalo Higuain sitting out a suspension, Zapata was handed the job of leading Napoli's attack and didn't wilt under the pressure.
Just after the hour the powerful Colombian striker sprung the offside trap on a Hamsik through-ball and although his shot was charged down, he got back up after stumbling to fire the rebound past Andrea Consigli.
Slovakian star Hamsik doubled Napoli's lead nine minutes later with a smartly taken curling effort from inside the area after Zapata had returned the favour by laying the ball back to him.
Napoli held on for victory, despite Mertens' red card, which Benitez attributed to their "winning mentality".
"It wasn't an easy game at all because Sassuolo played well, but once again we showed we have the right mentality," Benitez told Sky Sport before praising the input of Zapata.
"It's not easy to leave him on the bench but he just has to keep doing what he did today: score goals and create scoring opportunities."
Although Napoli overcame Higuain's absence, the Argentinian's suspension could hit his bid to claim the Serie A top scorer's award.
Until Inter's patchy win at Cagliari, Carlos Tevez had been leading the race on 14 goals but he has been joined by fellow Argentinian Mauro Icardi.
After a balanced opening half, Mateo Kovacic got Inter off the mark when he fired a loose ball past Zeljko Brkic after Icardi lost control of Lukas Podolski's cross.
Cagliari should have taken advantage of some disastrous Inter defending to get back on terms.
Andrea Cossu failed to capitalise on a howler from Nemanja Vidic to fire over, and Paul-Jose M'Poku's attempt to nutmeg Juan Pablo Carrizo saw the ball get stuck between the 'keeper's legs.
However, it was the visitors who showed their hosts how to convert chances as they doubled their lead.
Icardi's 14th goal of the campaign was a fine individual effort.
The Argentinian ran on to a through ball on the right before stopping and sending a curling shot with his left foot into Brkic's top right-hand corner.
Cagliari's second-half substitute Samuele Longo helped reduce the arrears on 74 minutes when his shot smacked off the post and went in of the back of Carrizo.
But Mancini's men held on for a win which moved them up to eighth, albeit 22 points behind Juventus.
"We came here to play for the three points and achieved our goal," Icardi told Sky Sport.
"We've changed the way we play under Mancini and we're doing well.
"It wasn't easy at the start, but we're getting more used to it now."