Last week, PSG were a win away from securing the French top-flight silverware but passed on the opportunity after Strasbourg held them to a 2-2 draw.
More intriguing was the manner at which they gave up the chance, with striker Choupo-Moting inexplicably missing an open net.
However, Sunday's encounter against second-placed Lille presented another chance to clinch the title again with just a point against their hosts enough. But the Parisians were humiliated 5-1, with Pepe scoring what was the winning goal while Choupo-Moting watched the entirety of the game from the sidelines.
Thomas Tuchel's side had started on the wrong foot as Thomas Meunier scored a seventh-minute own goal. However, Juan Bernat set them level four minutes later but the Spaniard saw a straight red card in the 36th minute to leave his team a man short.
Few minutes after the restart, Pepe strode past PSG's backline to help Lille retake the lead with a record-levelling 19th league goal of the season before Jonathan Bamba struck a third.
The Cote d'Ivoire international then provided assists for Gabriel and José Fonte's goals to cap off an impressive performance at Stade Pierre Mauroy, and deny his Cameroonian counterpart
Choupo-Moting, 30, started his career in Germany - where he was born - playing with for likes of Hamburg, Mainz 05 and Schalke 04 before moving to England to play for Stoke City in the Premier League, and has never won a title in his senior career.
After the Potters' relegation to the Championshipa last season, he made a surprise move to the French champions ahead of the 2018-19 campaign.
The former Germany U21 striker has made 18 appearances for the Parisians, scoring thrice.
Despite the gap between PSG and Lille closed to 17 points, the former have a third chance to seal league triumph - and their Cameroon international's first silverware - provided they grab at least a draw against Nantes in Wednesday's league fixture.