Lazio defeated city rivals Roma 2-1 on Sunday to move into third place in Serie A in a stormy derby which saw Roma goalkeeper Maarten Stekelenburg red-carded inside the first 10 minutes.
Stekelenburg was sent-off when he brought down German striker Miroslav Klose who had burst past Juan after springing the offside trap.
Roma's eighth red card of the season was compounded when Brazilian midfielder Hernanes scored from the penalty spot, beating replacement keeper Bogdan Lobont who had come on for Erik Lamela.
But Roma levelled after 16 minutes when Fabio Borini found the target after a Juan drive had come back off the post.
Lazio's one-man advantage eventually told in the second half when skipper Stefano Mauri volleyed home a free-kick from Cristian Ledesma in the 62nd minute as they celebrated a league double over their city rivals.
Lazio now have 48 points, three behind second-place Juventus and six off Milan in top spot while Roma are down in sixth place.
Goals by Edinson Cavani and Ezequiel Lavezzi gave Napoli a potentially crucial 2-1 success at Parma to take the southern outfit to within three points of the top four as they target a Champions League qualifying slot.
Cavani struck five minutes before the interval and Lavezzi bagged the winner with four minutes remaining after Cristian Zaccardo had threatened to rescue a point for a Parma side only five points clear of the drop zone.
Napoli moved onto 43 points from 26 matches with their fifth straight win, a run which have seen Cavani and Lavezzi plunder 10 goals between them.
But there was a touch of good fortune about their opener as Cavani bundled home having seen his initial penalty saved.
There was then an element of controversy as Argentinian Lavezzi appeared to be offside when he netted the clincher.
It was the Cavani-Lavezzi tandem which proved too hot for Chelsea in the first leg of their Champions League last 16 encounter, the pair sharing the goals in a 3-1 win -- and again they showed their poaching power.
Napoli are now fifth in the table, three points behind Udinese who were held 0-0 at home by Atalanta.
AC Milan still lead the way after they thrashed Palermo 4-0 on Saturday courtesy of a Zlatan Ibrahimovic treble on his return from suspension to move three points clear of Juventus, albeit having played a game more than their Turin rivals.
Juve maintained the only unbeaten record in Serie A but had to be satisfied with a 1-1 draw at home to Chievo.
Having drawn a bad-tempered clash with Milan last weekend, the Turin side went ahead against mid-table Chievo after 18 minutes thanks to Paolo De Ceglie, but their rivals rallied and Boukary Drame netted an equaliser on 76 minutes.
Later Sunday, Inter Milan take on mid-table Catania with coach Claudio Ranieri denying the axe is hovering after a dreadful run of seven defeats and a draw which dropped them to seventh, 12 points off a Champions League qualifying berth.
Ranieri said he would likely leave out Dutch star Wesley Sneijder, struggling to find his form, against Catania.
"It's not accurate to say Sneijder is a problem -- but he is not having his best year and you have to deal with that in a certain way," Ranieri explained.