Inter Milan's title charge gained momentum on Saturday as the champions squeezed past Cagliari 1-0 to close the gap on leaders AC Milan.
Inter's bitter city rivals can push their lead over their neighbours back out to five points with victory on Sunday at Chievo but the nerazzurri's ninth win in 11 league games ensured they kept up the pressure ahead of their Champions League clash with Bayern Munich on Wednesday.
Centre-back Andrea Ranocchia scored the only goal of the game in contentious manner as he appeared to be offside.
Inter coach Leonardo admitted the champions had struggled to get through this game.
"We did what we wanted to do, we scored early, we controlled the game but it was a big struggle," he told SkySport.
"We had balance in defence, we were at risk of conceding a goal for a long time, we created little.
"We suffered, we struggled to create chances and close out the game while Cagliari pushed men forward and they have quality players. It was very difficult."
The game began at break-neck speed with Cagliari goalkeeper Michael Agazzi plunging to his right to save a vicious Goran Pandev stike after just two minutes.
The visitors went straight up the other end and Inter shot-stopper Julio Cesar tipped over an Andrea Lazzari volley after a clever chip forward from Alessandro Agostini.
From Andrea Cossu's resulting corner Cesar tipped over a Daniele Conti header.
Inter took a controversial lead on seven minutes as Samuel Eto'o took advantage of Cagliari players arguing with the referee to take a quick free-kick.
He played in Houssine Kharja behind the defence and his deflected cross was kept out by Agazzi's leg only for the ball to rebound to the Morocco midfielder, who fired in a cross that hit Ranocchia and a defender on it's way in.
However, television replays showed Ranocchia had been offside as Kharja struck his shot.
Cagliari were straight back on the attack and Cesar tiped a skimming Davide Biondini shot around the post.
After that blistering first 10 minutes, the game settled a little, not in terms of pace but in terms of clear-cut chances.
On 21 minutes quick feet from Eto'o created a chance after a flowing Inter move but Agazzi got down well to stop his shot.
The Cameroon captain enjoyed the best of the rest of the half's chances but sent a free-kick over the bar before he had another shot comfortably saved by the Sardinians' goalkeeper.
The second period struggled to live up to the promise of the first and it wasn't until the 70th minute thata clear chance came by as Conti's strike from range deflected off Thaigo Motta and wrong-footed Cesar, only to plop the wrong side of the post.
By now Inter seemed to be paying for the efforts of their midweek win over Fiorentina and Cagliari were pushing hard for an equaliser, with Lazzari's rasping drive sailing just wide.
However, Leonardo moved to hold onto what he had and brought on Esteban Cambiasso, Dejan Stankovic and McDonald Mariga to shore up his midfield.
Earlier, Daniele Paponi scored a last-minute winner to earn Bologna a 1-0 victory against 10-man Palermo.
The visitors, who had Santiago Garcia sent off early in the second half, slumped to a second straight defeat and their Champions League hopes are now hanging by a thread after a second uninspiring performance in a row.
They sit seventh ahead of Sunday's games and already five points off a top four-finish.
Bologna, on the other hand, look to be safely in the mid-table comfort zone despite having been deducted three points for financial irregularities earlier in the season.