Juventus, who have a nine-point penalty from last year's match-fixing scandal, have 46 points from 24 matches, two points ahead of Napoli, who beat Triestina 3-1 on Saturday.
Modena's keeper Giorgio Frezzolini kept his side in the contest with a pair of good saves to keep out shots by Alessandro Del Piero and Pavel Nedved.
But he was beaten in the 86th minute, when Centurioni's attempt to cut out a Valeri Bojinov cross flew past him into the corner of the net.
