The league leaders' sixth successive victory never looked in doubt after they went ahead on eight minutes when Gianluca Curci parried Miralem Pjanic’s free-kick and Alessandro Florenzi was on hand to head home.
Gervinho got Roma's second nine minutes later with a powerful low effort, before Mehdi Benatia's close-range volley gave them a 3-0 half-time lead.
Close-season signing Gervinho scored his second of the match just past the hour mark, and Adem Ljajic completed the rout in the closing stages.
The result lifts Rudi Garcia's men back above Napoli and Juventus into first place in the table.
Earlier in the day, champions Juve came out victorious in the Turin derby as they beat rivals Torino at Stadio Olimpico.
The visitors generally created the better chances and Carlos Tevez went close on a number of occasions, while Torino keeper Daniele Padelli stopped Sebastian Giovinco capping off a fine team move.
Juve had to wait until the 54th minute before making the breakthrough though, as Andrea Barzagli’s initial header from a corner was diverted on to the crossbar, but Paul Pogba was on hand to nod in the rebound.
Substitute Mirko Vucinic almost added a second late on, but Padelli made another good save and Antonio Conte's side had to settle for a narrow win.
Meanwhile, Inter extended their unbeaten start to the season at Cagliari, but could only pick up a 1-1 draw despite having the better of the contest.
Ishak Belfodil and Ricky Alvarez both went close for Inter in the first half, but it was the latter’s half-time replacement - Mauro Icardi - who eventually opened the scoring.
With 75 minutes on the clock, the Argentine striker headed in from close range after an excellent run and cross from Yuto Nagatomo.
However, Radja Nainggolan cut in from the left and saw his low shot deflected past Samir Handanovic with just seven minutes left, earning Digeo Lopez’s side a point.
Meanwhile, Udinese’s erratic start to the campaign continued as they were defeated 2-0 by a German Denis-inspired Atalanta, with their former striker scoring both goals.
Hellas Verona’s impressive return to Serie A goes on thanks to a 2-1 victory over visitors and fellow promoted side Livorno, while Sassuolo picked up a 2-2 draw at home to Lazio - their second consecutive draw since losing 7-0 to Inter.
And in Sunday's other game, Catania picked up their first win of the season as Jaroslav Plasil and Lucas Castro gave them a 2-0 triumph over Chievo.
