Serie A leaders Inter Milan needed a Zlatan Ibrahimovic equalizer to draw 1-1 at home to dogged Cagliari on Saturday.
Jose Mourinho's side extended their lead to seven points after the Sweden striker tapped the ball in at the far post on 77 minutes following a superb run and cross by substitute Hernan Crespo.
Forward Robert Acquafresca, on loan from Inter, had put the Sardinians ahead 12 minutes earlier when he chested the ball down and fired home after defender Walter Samuel slipped.
Italy U-21 international Acquafresca later missed an open goal from close range, one of three good chances mid-table Cagliari had to snatch victory.
"We prepared really well and it has borne fruit," he told Sky television before reflecting on his glaring miss.
"It shows I must still improve a bit. It was a special match for me and I hope one day to wear the Inter shirt."
Inter were looking for their ninth successive league win and, although they dominated, the killer touch was elusive.
Ibrahomivic had three decent efforts and Samuel diverted the ball just wide before captain Javier Zanetti went close with two fierce drives.
Inter's Sulley Muntari struck the post in the second half and Mancini's effort was ruled out for offside late on.
Mourinho, who travels to watch Champions League last 16 opponents Manchester United play former club Chelsea on Sunday, took a risk by playing three at the back after going behind and the introduction of the little-used Crespo did the trick.
Earlier, Genoa rose to fifth with a 3-0 win over lowly Torino in the first game since the mid-season break.
(Agencies via China Daily January 12, 2009)
