Converted penalty opened the scoring before two second half strikes
The Lupi left Sardinia with their tail tucked between their legs after a 5-1 drubbing in their first meeting of the season but Francesco Totti, Simone Perrotta and Jeremy Menez ensured there was to be no sequel to that horror show.
The visitors came storming out of the starting blocks and almost silenced the Giallorossi faithful when Andrea Cossu cut in from the left-hand-side and curled a shot that looked destined for the top corner until Julio Sergio got a fingertip to the ball.
The game then took a dramatic turn when the hosts were awarded a penalty in the 21st minute after Michele Canini was whistled for dragging down Daniele De Rossi as he tried to get on the end of a Totti cross.
Totti stepped up and smashed a shot past Michael Agazzi to give Roma the lead against the run of play.
Marco Borriello had a golden opportunity to double the Lupi’s advantage when he pounced on a loose ball in the area and unleashed a low drive that Agazzi did well to keep out.
Cagliari continued their aggressive approach but were not able to pry open the home side’s defence and were a little unfortunate to head into the first-half interval one goal down.
Roberto Donadoni’s men came out all guns blazing after the break as Cossu took the ball down with an excellent first touch and pulled the trigger only to see Mexes make a vital block.
Robert Acquafresca and Radja Nainggolan also had chances but were unable to beat Julio Sergio.
De Rossi almost found the top corner with a long-distance effort in the 69th minute that forced Agazzi into action and from the ensuing corner the Cagliari keeper spilled Juan’s header and Simone Perrotta was on hand to tap home the rebound.The hosts then put the match to bed in injury time when Jeremy Menez beat the offside trap before rounding Agazzi and tapping the ball into the open net.
The win sees Claudio Ranieri’s side leapfrog Inter, Lazio and Napoli into second place with the rest of the round’s matches still to come on Sunday.