Miroslav Klose struck a superb late winner as Lazio beat Inter Milan 1-0 at the Olympic Stadium on Saturday to indirectly boost Juventus's hopes of extending their lead before Christmas.
Inter started their 17th match of the campaign only four points behind champions Juve at the top of Serie A, however Andrea Stramaccioni's men were dominated throughout and missed several chances late on.
Stramaccioni's anger showed as he walked off the pitch following a fifth defeat of the campaign which means Juventus can now extend their lead over Inter to seven points if they beat Atalanta in Turin on Sunday.
"We absolutely did not deserve to lose," insisted Stramaccioni, despite admitting Lazio had dominated the opening half.
"But it was a good goal from Klose. The result is what it is, and we accept it."
Lazio had beaten Inter only twice in their last 15 league games although one of those wins was last time out at the Olympic Stadium in March.
And with Lazio unbeaten at home since a shock 1-0 reverse to Genoa at the end of October -- combined with Inter's poor away form of late -- Vladimir Petkovic had every reason to believe his team could produce a result.
In comments to Sky Italia, the Bosnian coach said: "Tonight the team gave it 100 percent, in fact we only really suffered for 10 or 15 minutes in the second half.
"Now, we have to try and give the same commitment on our travels as well."
Inter threatened first, Federico Marchetti diving quickly to smother the ball as Diego Milito pounced on a chest-down following Yuto Nagatomo's looping cross from the right.
But the visitors created few chances in an opening half in which Cristian Ledesma saw a powerful shot from distance go just wide, while Stefano Mauri just failed to muster a shot from inside the area.
Lazio's claims for a penalty also fell on deaf ears after Klose tumbled to the ground next to Alvaro Pereira.
Stramaccioni tinkered with his formation at the interval, but although Inter came fighting back late on Lazio, despite a dubious start, remained in control.
At the end of a well-worked move Brazilian Hernanes sent a first-time shot high and wide from 20 metres.
The hosts were then lucky to escape when Fredy Guarin was allowed to power up the middle to unleash a shot which had Marchetti at full stretch, while moments later Milito's weak effort trickled wide of the keeper's post.
Inter finally had some momentum but Nagatomo failed to tap home after Antonio Cassano's well-placed shot from the Japanese defender's lay-off had come off the post after a superb parry by Marchetti.
Candreva's angled shot was then parried by Samir Handanovic while Klose was let down by poor control when he collected Alvaro Gonzalez's inch-perfect cross from the right while in alone on goal.
Klose's persistence, however, was to pay off, the German finally beating Handanovic with a well-placed strike from the edge of the area after running on to Mauri's incisive through ball.
Inter rallied and in the dying moments caused panic in the Lazio area but the hosts held on for a win which left them in fourth but level on points with third-placed Napoli.
Earlier an 89th minute strike from Udinese forward Antonio Di Natale allowed Udinese to snatch a 1-1 draw with Palermo who had opened their account thanks to Josip Ilicic's superb 33rd-minute strike.