Antonio Candreva netted both goals as Lazio defeated Serie A leaders Inter 2-1 in a contest which saw both sides reduced to 10 men at San Siro on Sunday.
With three minutes to go, the Italy international saw his spot-kick kept out by Samir Handanovic, but reacted quickly to tap home the rebound and secure the points.
Felipe Melo, who had been guilty of committing the foul which led to the penalty, then received a red card in the dying seconds of the game to make matters even worse for the hosts, before Lazio's Sergej Milinkovic-Savic was also dismissed deep into stoppage time.
Lazio had previously opened the scoring early on via Candreva after a clever corner routine, before Mauro Icardi found the net after a sublime through ball from Ivan Perisic just after the hour mark to level.
Roberto Mancini's men remain top of the Serie A table heading into the mid-season break, but saw Napoli and Fiorentina close to within one point, while Juventus and Roma also narrowed the gap and are trailing by three and four points, respectively.
For Lazio boss Stefano Pioli, however, it was a desperately needed victory after a run of two points from seven matches had seen pressure mounting on his position.
Despite their poor form, it was Lazio who struck first after five minutes following a corner routine. Lucas Biglia swept a neat pass to the unmarked Candreva on the edge of the area and he beat Handanovic with a powerful low shot at the near post.
The early lead allowed Lazio to sit back and defend deep, looking to hit Inter on the counter-attack with Felipe Anderson and Candreva's pace and trickery.
The home side, meanwhile, struggled to create any chances of note, and Lazio's tactics nearly paid off when Anderson set up Candreva inside the box after some sloppy play from Melo, but the goalscorer lifted his attempt over from five yards out.
Icardi restored parity in the 61st minute, though. Perisic set up the Argentine striker with a delicate through ball and Icardi kept his cool one-on-one with Etrit Berisha, placing the ball through the goalkeeper's legs for his seventh league goal of the season.
Inter continued to dominate proceedings and desperately pushed for a winner, but Lazio's defence held firm before Melo's first moment of madness handed them the chance to claim all three points.
The Brazilian needlessly fouled Milinkovic-Savic inside the area and Candreva found the net from the rebound, with Handanovic keeping out his initial attempt.
The drama did not end there, however, as Melo then saw a straight red card for dangerous play, kicking Biglia in the face with a high boot, with Milinkovic-Savic following suit after getting a second yellow for kicking the ball away.
