Lazio secured a controversial 2-1 derby win over bitter-rivals AS Roma who had goalkeeper Marten Stekelenburg sent off after eight minutes in Serie A on Sunday.
Hernanes put Lazio ahead from the penalty awarded as a result of Stekelenburg's foul on Miroslav Klose only for Fabio Borini to level six minutes later.
However, a 62nd minute goal from Stefano Mauri enabled Lazio to go third in the table and complete the double over their neighbours after winning by the same score earlier in the competition.
Ezequiel Lavezzi scored an 86th minute goal to give Napoli a 2-1 win at Parma in another of Sunday's games while Udinese dropped to fourth after being held 0-0 at home by Atalanta.
Lazio, in the Champions League playoff spot, have 48 points from 26 games, two ahead of Udinese. AC Milan lead with 54 points while Juventus, who have a game in hand, have 51.
The Rome derby got off to a fiery start when Klose broke through and appeared to be tripped by Stekelenburg.
After taking his time to decide, the referee awarded a penalty and dismissed the Dutch goalkeeper amid furious Roma protests.
Brazilian midfielder Hernanes gave replacement goalkeeper Bogdan Lobont no chance from the penalty and celebrated with an ambitious somersault.
Roma levelled when defender Juan's shot hit the post and Borini tapped in the rebound before Giuseppe Biava could clear.
After that, there were chances at both ends in a match also marred by constant histrionics and angry protests over almost every refereeing decision.
Lazio snatched the winner in the 62nd minute when Mauri was left unmarked and guided Cristian Ledesma's free kick into the far corner.
Hernanes could have sewn up the game when he was sent clean through shortly afterwards but delayed too long over his shot which was blocked by Lobont.
Instead, Lazio, who had Lionel Scaloni dismissed in the 86th minute for a second yellow card, had to sweat out the last few minutes and had a lucky escape from Francesco Totti headed narrowly wide.
Lazio indulged in copious amounts of time-wasting and had substitute Mobido Diakete booked for taking the field before the player he was replacing had left, in what appeared to a ploy to hold up play further.
There was also controversy at Parma where Napoli's Lavezzi scored an 86th minute winner with the hosts claiming he was offside.
Cavani had given Napoli the lead before halftime, scoring from a rebound after his own penalty was saved by Antonio Mirante for his 16th league goal of the season.
Cristian Zaccardo levelled for Parma in the 72nd minute.
Fiorentina beat bottom club Cesena 2-0, Lecce drew 2-2 at home to Genoa and Siena beat Cagliari 3-0 in Sunday afternoon's other games. Troubled Inter Milan were at home to Catania in an evening game (1945).