Allegri, who has won four league and cup doubles in as many years at Juventus, has been linked in media reports with a move to Premier League clubs Arsenal and Chelsea.
Juve could not capitalise, although they were content with the point as Allegri's side completed the double just days after their 4-0 victory over AC Milan at the Stadio Olimpico.
"We work hard, but when it's time to celebrate after four extraordinary years, it's right that everyone celebrates".
But Juventus did not take advantage of their advantage as they game lost its momentum although Dybala did have penalty appeals. "The manager demonstrated that he is great and I think our relationship can go on". "Credit goes to the lads for keeping their cool, taking things one step at a time towards our final objective".
Needing just a draw to wrap up a 34th top flight title - to add to their Italian Cup won in midweek - Juve survived a bright Roma start which saw Edin Dzeko and Nainggolan fire over.More news: Talks between North Korea and United States less than a month away
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Paulo Dybala threatened early and broke through early in the second half after an Alex Sandro cross but the goal was disallowed because the Argentina striker was offside.
Sarri repeated his complaint that Juventus habitually played their matches before Napoli.
"Juventus have a special mentality that has been built up through the years", Di Francesco said. "Having a team with human values as these players have them makes it easier to reach all your targets".
However, Sampdoria goalkeeper Belec was finally beaten in the 72nd minute with a left-footed strike from outside the box from Arkadiusz Milik to give Napoli the lead, 0-1.
Fiorentina remained eighth, three points behind Atalanta and the final Europa League spot.