Internazionale made it ten wins on the spin in Serie A with a hard-fought success at Lazio.
Roberto Mancini's men have carried all before them in the last couple of months and they passed a major test on Wednesday with flying colours.
Esteban Cambiasso's close-range finish following a fine run from Hernan Crespo set them on their way to three points, but they were made to work hard in the second half and had to play for over 45 minutes with ten men as Zlatan Ibrahimovic was sent off just before the break.
Lazio pressed hard for a leveller, but the wind was taken out of their sails five minutes from time as Marco Materazzi climbed high to head home a free-kick.
Roma are giving chase and they were able to take maximum spoils at Torino.
Francesco Totti netted the opener on 37 minutes and the points seemed safe when Alessandro Mancini doubled the lead ten minutes from the end. The home side reduced the arrears through Alessandro Rosina a minute from time, but the capital club held on for the win.
Palermo cemented their position in third as goals from Mark Bresciano, Eugenio Corini, Giovanni Tedesco and Ciro Capuano saw off bottom club Ascoli.
Livorno's Uefa Cup hopes suffered a blow as they were thrashed at Sampdoria.
The visitors took the lead on 12 minutes through Luca Vigiani, but Samp hit back in style and goals from Daniele Franceschini, Francesco Flachi and Fabio Quigliarella (2) secured a comfortable win.
Milan have had an indifferent season, but they secured a welcome pre-Christmas fillip as Kaka inspired them to a win over Catania. The Brazilian scored twice, with the third coming from Alberto Gilardino, as the Rossoneri proved too good.
A brace from Luca Toni handed Fiorentina a 2-0 win at Cagliari, while Empoli secured a narrow win over Siena thanks to Francesco Marianini's goal just after the interval.
Chievo showed tremendous resilience to overcome a stern challenge from struggling Reggina.
Nicola Amoruso fired Reggina ahead on 16 minutes, but they were behind by half-time thanks to goals from Paolo Sammarco and Federico Cossato.
Reggina hauled themselves level through Francesco Modesto 12 minutes from time, but Simone Tiribocchi popped up two minutes from the end to secure victory for Chievo.
Udinese came from a goal down to pinch a last-gasp win at Atalanta.
The home side led a minute after the break through Fernando Tissone, but Raffaele de Martino levelled the scores within five minutes.
De Martino turned villain on 71 minutes as he was dismissed, but it did not stop his team-mates from taking the points as Antonio Di Natale netted five minutes into injury-time.
Messina and Parma played out a 1-1 draw, with Daniele Paponi's goal cancelling out an effort from Arturo Di Napoli.
Click below for a match summary:
Milan v Catania
Atalanta v Udinese
Cagliari v Fiorentina
Chievo v Reggina
Empoli v Siena
Lazio v Internazionale
Messina v Parma
Palermo v Ascoli
Sampdoria v Livorno
Torino v Roma