Maurizio Sarri's side shrugged off the disappointment of their Coppa Italia final defeat to Napoli last week, Ronaldo setting them on their way from the penalty spot in the 23rd minute in their first top-flight game since March 8.
Dybala added a superb second before half-time, whipping into the top corner from outside the penalty area, while Ronaldo and Federico Bernardeschi came close to adding further goals after the interval before Danilo was sent off in stoppage time.
The result moves the reigning champions four points clear of Lazio at the Serie A summit, although Simone Inzaghi's side will have the chance to cut the gap back to one point when they travel to Atalanta on Wednesday.