They had another opportunity this weekend against second placed Lille, but they failed in spectacular fashion.
It was 1-1 going into half-time but, Lille scored four times in the second 45 minutes to inflict PSG's heaviest defeat since 2010.
PSG had another chance against Nantes on Wednesday night and unbelievably, they fell to another defeat.
Three minutes after, Brazilian defender Diego Carlos powered home captain Rongier's cross to restore parity for the home side.
Marquinhos, Marco Verratti, Neymar, Thiago Silva, Thomas Meunier, Edinson Cavani, Angel Di Maria and Juan Bernat were not included in Thomas Tuchel's squad list due to injuries and suspension, while the German coach also dropped Kylian Mbappe from the squad.
Majeed Waris padded Nantes' lead minutes before halftime and Carlos added another in the 55th minute.
Thus, Tuchel was only able to name five substitutes.
PSG needed a lift after their crushing loss to Lille and appeared to have it when wing-back Alves lashed a sweet 30-yard strike over Maxime Dupe in the 19th minute.
Eric Choupo-Moting hit the post for PSG before 20-year-old Guclu pulled a goal back with a minute left but it proved to be too little, too late.
PSG now hold a 17-point lead over Lille with six games to go.
Thomas Tuchel's side, who have now picked up only one point from their last three Ligue 1 outings, will be crowned champions on Sunday if they beat Monaco at home.
Nantes F.C seem comfortably on the league table as they are now 14th and will play 17th placed Amiens S.C on Sunday in the round 33 game of the ongoing competition.