Milan and Juventus started the day level on points but the Rossoneri's failure to break down Carlo Ancelotti's old side handed top spot to the reigning champions.
Udinese had stunned the Stadio Delle Alpi crowd by grabbing the lead on 66 minutes through Marek Jankulovski.
But the goal roused Juve from their slumber and the hosts rattled in four goals in the final 11 minutes to secure an ultimately convincing victory.
Substitute Marco Di Vaio, who replaced the returning Alessandro Del Piero, poached the equaliser in the 79th minute.
Fellow sub Fabrizio Miccoli put the hosts in front with five minutes left before Di Vaio and David Trezeguet netted to hand Juve the points.
Roma won a hard-fought but typically dramatic Rome derby over rivals Lazio with two late goals in the final nine minutes at the Stadio Olimpico.
A 0-0 first half saw little in terms of clear cut chances and it was not until the second period that play started to open up.
Francesco Totti went close to scoring by hitting the outside of Lazio's post with a low shot that beat a diving Matteo Sereni.
It was then the visitors turn to take the match to Fabio Capello's men, as Lazio's Dejan Stankovic squandered a couple of chances to break the deadlock.
But with nine minutes to go, Roma fans were sent into raptures as Brazilian Emanuele Mancini cheekily flicked Antonio Cassano's free kick from the right-hand side at the near post with the inside of his right foot past Sereni to make it 1-0.
Five minutes later, Roma sealed derby victory as Mancini hit a cross field ball on the break to fellow Brazilian Emerson.
He controlled the ball superbly and struck it right footed past Sereni for 2-0.
Inter revived their title aspirations with a comfortable 3-0 home triumph over winless Ancona.
Julio Cruz opened the scoring on 26 minutes and second half goals from Marco Materazzi and Christian Vieri wrapped up the win.
Chievo Verona finished their match at Siena with just nine men but managed to hold out for a 2-1 success.
A brace from Sergio Pellissier put Chievo in control before Lorenzo D'Anna and Franco Semioli were both dismissed for second bookable offences.
Enrico Chiesa's 77th minute penalty set up a nervy finale but Chievo clung on for the three points which send the Flying Donkeys into the top half of the table.
Perugia are still searching for their first Serie A win of the season after twice coming from behind to snatch a 2-2 draw at home to Lecce.
Javier Chevanton's sixth minute goal put the visitors in the ascendancy but Perugia levelled on the stroke of half time through Massimo Margiotta.
Cristian Ledesma's 55th minute strike put Lecce back in front but Fabio Grosso chiselled out a point for the hosts in the closing ten minutes.
Nicola Campedelli earned Modena a point at Reggina after Stefano Dall'Acqua had given the home side a 31st minute advantage.
Click below for an individual match summary:
Serie A
Internazionale 3-0 Ancona
Juventus 4-1 Udinese
Parma 0-0 Milan
Perugia 2-2 Lecce
Reggina 1-1 Modena
Roma 2-0 Lazio
Siena 1-2 Chievo
Click here for an updated Serie A table.
