Rome: Serie A champions Inter Milan on Saturday moved into second position two points behind AC Milan through a 1-0 win snatched with an own goal against visiting Cagliari.
The Sardinia guests protested fiercely after falling behind on seven minutes as Michele Canini flicked past Michael Agazzi.
The Cagliari defender stunned his own goalkeeper in an attempt to mark Andrea Ranocchia, who appeared to be off-side when his team-mate Houssine Kharja fired home after a free-kick action.
Inter fans at the Giuseppe Meazza watched a high-paced start, with Goran Pandev forcing Agazzi to a diving save in the second minute and home custodian Julio Cesar slapping a drive from Andrea Lazzari and a Daniele Conti header out of bounds.
There were no further threats from Cagliari despite their constant pressure and Inter had two more chances before the break when Giampaolo Pazzini nodded wide and Cameroon bomber Samuel Eto'o fired two feeble and central drives.
A wide drive from Lazzari opened a second half that saw Inter struggle in defence, but manage to clinch their ninth win from 13 home games.
With 12 games left to the end of the season, the Nerazzurri leapfrogged Napoli, who can claw back second place when they welcome struggling Catania late Sunday, after Milan visit mid-table side Chievo.
In an earlier weekend opener, young substitute Daniele Paponi scored a late winner for Bologna in a 1-0 defeat of 10-man guests Palermo.
The hosts moved 10 points clear of the three-team drop zone with a game in hand to be played next week against Roma.
Palermo suffered a second consecutive defeat, but remained in seventh place just one tier below the Serie A zone that grants a berth in European competitions.