Strike duo Fernando Llorente and Carlos Tevez struck in the second half as Antonio Conte's men secured a fifth consecutive victory without conceding a goal despite being depleted by injuries.
The champions' lead may be short-lived, with Rudi Garcia's Roma side facing Cagliari on Monday, but they are looking ominous and enjoyed another profitable weekend as Napoli, Inter and Fiorentina all failed to win.
Inter found themslves behind at Bologna after Panagiotis Kone netted in the 12th minute and although Jonathan dragged them back into it in the second half, they were unable to find a winner and had to settle for a 1-1 draw.
Fiorentina slipped up at Udinese as a 34th-minute goal from defender Thomas Heurtaux - his second of the campaign - consigned the Florence outfit to a 1-0 defeat.
Sunday's action was not so fruitful for bottom-of-the table Catania either as they lost 4-1 to Torino, with Omar El Kaddouri scoring a brace for the home side, while Atalanta were consigned to defeat at Sassuolo.
That 2-0 victory courtesy of goals from Simone Zaza and Domenico Berardi saw Eusebio Di Francesco's men extend their unbeaten league run to three despite the dismissal of Luca Antei for a second yellow card.
New Sampdoria boss Sinisa Mihajlovic was denied a win in his first game in charge as Lorik Cana's injury time goal salvaged a 1-1 draw for Lazio.
Roberto Soriano put the home side - who had lost their previous three games - in front in the 67th minute, but they were reduced to 10 men when Nenad Krsticic was shown a second yellow card and Cana made Lazio's numerical advantage count right at the death.
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