The capital club shocked Inter Milan 3-0 at San Siro on Saturday night to leave Juve and Napoli both five points adrift and, after the Azzurri narrowed the gap by beating Livorno, the Turin club's mission to catch up started poorly.
Sulley Muntari gave Milan the lead after only 19 seconds of play at the Juventus Stadium but Andrea Pirlo soon levelled with a free-kick against his former club.
For a while the game seemed to be heading towards a bad-tempered draw, until Sebastian Giovinco scored from the bench with Giorgio Chiellini compounding Milan's misery after visiting defender Philippe Mexes was sent off.
Muntari would double his personal tally on the stroke of full time but it was too little, too late for Milan.
Saturday night saw the Giallorossi beat Inter Milan to win a seventh game in a row, leaving title rivals Napoli and reigning champions Juventus both five points adrift.
But after Goran Pandev made the early breakthrough in Naples, further goals from Gokhan Inler and Jose Callejon guaranteed the Azzurri would close to within two points of the capital club before Marek Hamsik added a fourth at the death.
Lazio missed the chance to move up to fifth place after a goalless draw with Fiorentina at the Stadio Olimpico.
Lazio did most of the running, creating enough chances to win the game, but failed to beat Fiorentina goalkeeper Neto.
The visitors appeared tired from their Europa League exertions on Thursday and will have been the happier of the two sides with the point.
Winless Sampdoria rescued a 2-2 draw at the death to stun Torino in Serie A.
The visitors had come from behind and were seconds away from their third win of the campaign when Samp substitute Citadin Eder was fouled in the area and the referee pointed to the spot.
Eder made no mistake to earn his team a vital point.
Hellas Verona claimed their first Serie A away win in style with an emphatic 4-1 victory at struggling Bologna.
Goals from Fabrizio Cacciatore and Juan Iturbe gave the visitors a commanding 2-0 half-time lead at the Stadio Renato Dall'Ara.
Alessandro Diamanti pulled a goal back from the penalty spot shortly after the restart, but Luca Toni swiftly restored Verona's two-goal cushion before Jorginho Freiro sealed matters in stoppage time.
Udinese climbed into the top half of the table while prolonging their impressive unbeaten home run with a 2-0 victory over Cagliari.
Francesco Guidolin's men have lost all three of their games away from the Stadio Friuli in the new campaign but goals from Danilo and Antonio Di Natale secured a third win on home turf, where they last suffered a league defeat in September 2012.
Udinese are now seventh after extending Cagliari's winless run to a sixth game, while Diego Lopez's 14th-placed side remain winless on the road since February and only four points above the relegation zone.
A late own goal from Nicola Legrottaglie handed Genoa a valuable point from a 1-1 draw at Catania.
The Sicilians were within sight of only a second win of the season thanks to Pablo Barrientos' goal on the hour mark, but their former Juventus defender Legrottaglie headed the ball into his own net three minutes from time.
The result leaves Genoa and Catania with five points apiece and tied for 15th place after seven games.
Parma heaped further misery on rock-bottom Sassuolo with a 3-1 victory in a match which saw both sides reduced to 10 men.
Eusebio Di Francesco's promoted side have picked up just two points so far this term, but things looked promising at the interval when substitute Domenico Berardi stroked home a penalty in first-half stoppage time - following the dismissal of Parma goalkeeper Antonio Mirante - to get the visitors back on level terms after Raffaele Palladino's 32nd-minute opener.
However, the 10-man hosts showed little mercy on their struggling opponents and bagged two goals in seven minutes through substitute Aleandro Rosi and Antonio Cassano to seal the three points before Francesco Magnanelli's late red card rubbed salt into Sassuolo's wounds.
All three goals came in the first half with 37-year-old Totti opening the scoring in the 18th minute before adding a second with a 40th-minute penalty following a foul by Alvaro Pereira on Gervinho inside the area.
Alessandro Florenzi then notched a third four minutes later to complete a dream half for Roma, who even coped with the 79th-minute dismissal of Federico Balzaretti to claim a seventh successive win.
Roma, who are enjoying their best-ever start to a Serie A season, are now five points clear at the summit above Napoli, who are at home to Livorno on Sunday.
Inter, meanwhile, remain in fourth place on 14 points after seeing their unbeaten start to the campaign shattered.
Also on Saturday, Atalanta took all three points for a second successive game as Maximiliano Moralez's early strike steered them to a 1-0 win at Chievo.
Moralez netted what proved to be only goal of the contest in the 16th minute, volleying in from Christian Raimondi's tee-up.
The victory follows the 2-0 home league win over Udinese last weekend, prior to which Atalanta had lost three matches in a row.
Struggling Chievo, meanwhile, are now on a three-game losing streak themselves and have been defeated in a five of their seven league fixtures this season.