Inter extends impressive winning streak
Giampaolo Pazzini scored a controversial winner as Inter Milan came from behind to beat Lazio and move above their opponents into fourth place in Serie A.
Tommaso Rocchi put the visitors in front after half an hour, but Diego Milito levelled just before the interval.
Pazzini then scored when he should have been flagged for offside in the 63rd minute to earn the Nerazzurri victory, with a seventh straight Serie A win putting them just three points behind third-placed Udinese.
Rocchi scuppered a glorious chance to put Lazio in front in the 14th minute when he capitalised on a mistake by Lucio, but appeared to lose his balance as he was about to shoot and his weak shot trickled agonisingly against the post.
The striker made up for his miss after half an hour, though, when he needed just one touch to turn and place Ledesma's through-ball past Julio Cesar from eight yards.
Ricardo Alvarez provided Inter's first real moment of danger five minutes later but his pass was just too far in front of Yuto Nagatomo and Federico Marchetti was able to pounce on the ball first.
There was nothing the Lazio goalkeeper could do to prevent Milito from levelling just before half-time, though.
Again, Alvarez was involved, returning Milito's pass into the path of the Argentinian striker, who provided a perfect finish into the far corner.
The game remained on a knife edge with both sides effectively waiting for a mistake from their opponents.
However, it was a misjudgement by the linesman which enabled Inter to take the lead as Pazzini latched on to Lucio's long header from an offside position to lob the ball over Marchetti and into the back of the net.
Miroslav Klose wasted his first real chance of the game in the 65th minute, shooting straight at Julio Cesar from level with the penalty spot after reaching Rocchi's pass.
There were appeals from every Lazio player inside the penalty area when Lucio blocked a corner with his arm, but the referee had already stopped play for a push in the back of the Brazilian from his former Bayern Munich team-mate Klose.