Mario Balotelli scored his third goal in two games for AC Milan to snatch a share of the points in a 1-1 draw at Cagliari on Sunday as Roma's slump continued with a 3-1 defeat to Sampdoria.
AC Milan remain fourth, 14 points behind leaders Juventus but will drop to fifth if city rivals Inter account for Chievo at the San Siro in Sunday's late game.
Balotelli, signed from Manchester City 10 days ago, grabbed a brace, including one goal from the penalty spot, in a 2-1 win over Udinese last week.
But despite securing a share of the points in Sardinia, the striker spurned several chances to secure all three points for Milan during a finale in which the visitors belatedly laid siege to the Cagliari goal.
Milan coach Massimiliano Allegri admitted: "It was a tight game and we did well to hold out in the first half before we conceded the goal right just before half-time.
"We pulled our socks up in the second half and after the penalty when we created a few chances we should have put the match beyond reach. But overall it was a good point for us."
Cagliari, who won a last gasp bid to stage the match at their new Is Arenas stadium despite official fears over security, dominated the first half and took a 45th-minute lead through Victory Ibarbo's close range header.
It was the Colombian's first goal this season for Cagliari, who looked set to grab a precious victory until Milan levelled late in the match.
In a goalmouth melee, Balotelli prepared for an overhead kick but was impeded by Cagliari defender Davide Astori, who was sent off for a second bookable offence as the referee pointed to the spot.
The Italy international stepped up to send Michael Agazzi the wrong way to level and claim his third goal in two games.
Yet the 22-year-old was guilty of missing a superb chance to put the visitors ahead, and twice found himself offside while presented with goal-scoring chances in the final 10 minutes.
First, Balotelli's attempt to head Philippe Mexes's header from the edge of the area past Agazzi from close in went straight at the 'keeper.
He was then offside when Bojan flicked the ball into his path, and offside again when he tried to nod home the rebound from the Spain international's probing 20-metre drive.
Roma suffered their 10th defeat of the campaign, a result, which coupled with Udinese's 1-0 home win over Torino, dropped them to ninth place.
Roma sacked coach Zdenek Zeman last week after a humiliating 4-2 home reverse to Cagliari.
However, caretaker coach Aurelio Andreazzoli has work to do if he is to plug the holes in Roma's defence which has now conceded 45 goals.
Paraguayan midfielder Marcelo Estigarribia broke the deadlock on 56 minutes with a low angled drive and the hosts doubled their lead on 73 minutes when second-half substitute Gianluca Sansone rifled a freekick past Maarten Stekelenburg.
Argentine midfielder Erik Lamela reduced arrears two minutes later, however Sampdoria secured the win when Argentine Emanuele Icardi was left unmarked to beat Stekelenburg at the back post from a 77th minute corner.
"Sampdoria deserved the win," said Andreazzoli.
"A few decisions could have gone our way and I'm satisfied with how the lads played, but I'm not happy with the result."
Juventus, who face Celtic in Glasgow in the first leg of their Champions League last 16 tie on Tuesday, beat Fiorentina 2-0 on Saturday and now have a five-point lead on Napoli after they could only sneak a 1-1 draw at Lazio.