Lille retook control of Ligue 1 on Saturday after Jonathan David's first-half goal separated the sides at the Parc des Princes.
PSG, fielding nearly 500 million euros worth of attacking talent in the shape of Neymar, Kylian Mbappé and Angel Di Maria, dominated the early stages.
The troika combined several times to test the Lille goalkeeper Mike Maignan but they failed the make the breakthrough as the game became embroiled in niggly fouls.
One cost PSG dearly in the 20th minute.
The free-kick just inside the PSG half resulting from Idrissa Gana Gaye's crude hack on David was taken quickly.
Jonathan Ikone strode on and found David unmarked in the PSG penalty area. The Canada international's shot went past the PSG goalkeeper Keylor Navas via a deflection into the top right hand corner.
The last meeting between the sides in the last 16 of the Coupe de France at the Parc des princes produced a 3-0 stroll for PSG.
Just over a fortnight later, Lille exuded collective grit and fight. The hosts, lacking the calming creative presence of the injured Marco Verratti, racked up five bookings as they tried to outmuscle their visitors.
When PSG did get a chance in the second-half to draw level, the expensively assembled strike force fluffed their lines. Neymar screwed a header wide from Marquinhos' cross in the 69th minute and Mbappé's attempts to cut in from the right flank ran into a wall of white shirts. Both were cautioned as their frustrations boiled over.
Lille could have made it safe 10 minutes from time when Timothy Weah set up Burak Yilmaz but the 35-year-old veteran - who scored four times on international duty for Turkey in the recent 2022 World Cup qualifiers - fired straight at Navas.
A goal might have prevented the ugly scenes at the end. Neymar picked up his second booking and was sent off after pushing over the Lille defender Tiago Djalo who was given a second yellow for clutching his face when pushed in the back.
Lille, however, managed to emerge from the theatrics unbreached to inflict a fifth home defeat on the reigning champions.
With seven games remaining, Lille lead the pack with 66 points, PSG are second with 63.
"Every time we lose it's the same, we're lacking intensity," said Marquinhos. "Several players were coming back from international duty but it can't be an excuse.
"We have to be more solid and more consistent. Too many teams are winning here."
Monaco lie a point behind PSG following a 4-0 romp past Metz. Cesc Fabregas started the spree from the penalty spot after 50 minutes. Before the visitors could recover, Kevin Volland doubled the advantage.
Wissam Ben Yedder added the third mid-way through the second-half and the France international got his second and his side's fourth from the penalty spot in the 89th minute.
Monaco coach Niko Kovac admitted his side were in with a chance of the title. "There are still 21 points at stake," said the former Croatia international. "But first we first need to secure a place in next season's Champions League. We are in good form. We have a good momentum."