It took a 72nd-minute goal from Massaro to break the deadlock when he raced unmarked into the penalty area to fire home a low cross from Christian Panucci. As Piacenza pushed forward, Papin grabbed a typical opportunist goal, seizing on a loose ball to score.
That result ended the champions' run of three successive games without scoring and capitalised on a 1-1 draw between the two teams sharing second place - Sampdoria and Juventus.
An 88th-minute free-kick from Fabrizio Ravanelli kept Juve's fading title hopes alive after Attilio Lombardo's 29th-minute penalty had given the home team a first-half lead. Samp's David Platt sustained an injury and was unable to complete the match against his old club.
Parma tightened their grip on fourth spot with a convincing 2-0 win over Lazio. Only inspired goalkeeping from the Italian international, Luca Marchegiani, kept the scoreline respectable - although he had no answer to Faustino Asprilla's spectacular overhead kick late in the game.
Internazionale's much-criticised Dutch internationals, Dennis Bergkamp and Wim Jonk, played key roles in their side's impressive 4-1 victory at Cremonese. Jonk scored two first-half goals to take his season's tally to six, while Bergkamp set up the third goal for Antonio Paganin. Ruben Sosa added a fourth in the 80th minute.
In Serie B, the Argentine striker, Gabriel Batistuta, struck twice in Fiorentina's 4-1 victory against Palermo which kept the Florentine team on top.