The two title chasers meet at the Stade Lille-Metropole on Saturday hoping to close the gap on first-placed Montpellier HSC.
With five games remaining, PSG trail La Pallaide by two points, while Lille are a further five adrift in third.
The Italian said that this weekend could prove to be the defining moment of the Ligue 1 season.
"It's possible that this next match could hold the key to our entire season," www.ligue1.com quotes the Italian as saying. "It'll be an important matchday for all of the top three sides, perhaps the most important of the season."
Montpellier travel to Europe-chasing Toulouse on Friday.