There was no lack of drama at Juventus Stadium, with referee Gianluca Rocchi awarding three penalties - two to the hosts and one to Roma - in a first half which finished 2-2.
The match looked destined to end level, but Leonardo Bonucci netted in spectacular fashion with four minutes left, volleying past Lukasz Skorupski from just outside the area to stun Roma.
Carlos Tevez scored two penalties in the first half after controversial decisions from Rocchi, who also sent Roma coach Rudi Garcia to the stands, but the Argentine forward's two goals sandwiched a Francesco Totti spot-kick and Juan Iturbe's 44th-minute strike for the visitors.
Juve substitute Alvaro Morata and Roma defender Kostas Manolas were sent off in the dying stages as Rocchi again found himself in the spotlight, but the champions held on to claim a fifth successive home win against the capital club to go three points clear at the top of the table.
Fiorentina kick-started their Serie A campaign as a 3-0 triumph over Inter gave them their first home win of the season.
Inter were aiming to provide a reaction to their humiliating 4-1 defeat at home to Cagliari in their last Serie A fixture, but Khouma Babacar's powerful 25-yard drive after only seven minutes saw them fall behind.
The injury-hit hosts doubled their lead 12 minutes later as the fit-again Juan Cuadrado tried to better Babacar's effort, netting an exquisite finish of his own after cutting in from the left.
Nenad Tomovic put the result beyond doubt towards the end, increasing the pressure on Walter Mazzarri.
One coach on whom the pressure is easing is Rafael Benitez, as Napoli recorded a third consecutive win in all competitions on Sunday, beating Torino 2-1.
Fabio Quagliarella netted for the third successive Serie A game to give the visitors a first-half lead, but Napoli battled back in the second period thanks to goals from Lorenzo Insigne and Jose Callejon.
Udinese were unable to move level on 15 points with second-placed Roma as they were surprisingly held to a 1-1 draw at home to Cesena, Emmanuel Cascione's 90th-minute penalty cancelling out Bruno Fernandes' opener.
Atalanta slumped to a fourth league defeat in a row as hosts Sampdoria ran out 1-0 winners, moving them up to third, and Lazio edged a five-goal thriller 3-2 at home to Sassuolo, with Lorik Cana and Federico Peluso seeing red.
Like Sassuolo, Palermo continue their search for a first win of the season as they were comfortably beaten 3-0 at Empoli, while Alessandro Matri's 90th-minute strike earned Genoa a 2-1 triumph at struggling Parma.
