(CNN) -- AC Milan missed the chance to leapfrog city rivals Inter at the summit of Serie A after being held to a 1-1 draw by Napoli in the San Siro on Sunday.
A victory would have seen Milan go top for the first time this season but it was Napoli who went ahead after 13 minutes through Hugo Canpagnaro before Filippo Inzaghi headed the equalizer 13 minutes later.
The draw sees Milan stay in second spot, one point behind champions Inter, who were held to a 1-1 draw at Palermo on Saturday.
Third-placed Roma are three points adrift but meet Inter next Saturday in a decisive clash.
Milan are bidding for their first Italian championship since 2004, but have lost David Beckham and Aleessandro Nesta to serious injuries in the past week.
Milan coach Leonardo gambled on the fitness of Brazilian striker Pato, but he limped off shortly after Campagnaro had taken advantage of laughable home defending as Christian Abbiati and Massimo Oddo collided to leave him a simple chance.
But Pato's fellow Brazilian Ronaldinho set up Inzaghi for a simple headed goal after a clever piece of play and fine cross.
Napoli, who are still chasing a Champions League place, had chances to reclaim the lead and home keeper Abbiati had to show his mettle either side of the break.
Milan also had opportunities in an entertaining game and Inzaghi and Mancini were denied by fine saves by Morgan De Sanctis.
"It's never easy playing Napoli. We had a few chances after the goal but it wasn't to be," Ronaldinho told AFP.
"There are ten games left to give it our all. We need to take the positives from the game and keep our feet on the ground. If we do, the scudetto is a real possibility.
In other key results on Sunday, first-half strikes from Tommaso Rocchi and Sergio Floccari gave Lazio a 2-0 win at Cagliari, to boost their battle against relegation.
Bari and Parma shared the spoils with a 1-1 draw to stay in mid-table with Chievo and Catania also ending 1-1.
Sampdoria later completed a miserable week for Juventus with a 1-0 home win in the battle for the final Champions League spot.
Juve, shocked by Fulham in the Europa League, were beaten by a superb long range strong from Antonio Cassano for Samp, who go fifth.