The title could be tied up by next Sunday when Juventus and Napoli go head-to-head in a top of the table clash in Turin.
Juventus would have to win on Wednesday at Crotone and Napoli lose at home against Udinese, while the champions would also have to win next Sunday's game for the title to be decided.
"Napoli are having a sensational campaign, they are still right up there and I think the next two games could be almost decisive for the Scudetto," said Juventus coach Massimiliano Allegri.
"We are absolutely not favourites for the Scudetto. I want to thank everyone today, because it’s not easy to win like this after such a draining experience as the Champions League."
Juventus showed they had put their midweek Champions League defeat to Real Madrid behind them as they were greeted with a banner "Proud of You" and applause for captain Gianluigi Buffon who was sent off in Madrid.
Brazilian Douglas Costa was the architect of the victory coming off the bench in place of the injured Miralem Pjanic to set up all three goals.
Costa crossed for Mario Mandzukic who volleyed under the bar just before the break, and dinked another for Benedikt Howedes whose diving header found the mark on the hour mark.
The Brazilian then set-up Sami Khedira for the third with 15 minutes to go, with Buffon denying Duvan Zapata a late consolation goal for Sampdoria.
"Douglas Costa was meant to come on, not quite that early, but it was part of the plan," said Allegri.
"We played with focus, calm and intelligence. Then Pjanic did the rest! He just had a thigh twinge and it was best to come off."
Juventus now have have 84 points from 32 games, six ahead of second-placed Napoli with six games to go.