Ten-man Lens denied Paris Saint-Germain a second trophy in five days as Florian Thauvin's first-half goal secured a 1-0 victory in the French Champions' Trophy on Sunday.
Lens were worthy winners in their first match under new coach Dino Toppmoeller, adding to the French Cup title they won under previous boss Pierre Sage in May.
PSG, who beat Aston Villa on Wednesday in the UEFA Super Cup, struggled to find their flow at Lens' Stade Bollaert-Delelis, despite their hosts having Kyllian Antonio sent off in the first half.
Luis Enrique's men will turn their attentions to the start of their Ligue 1 title defence at home against Rennes in a week's time.
They will be without Portugal defender Nuno Mendes for that match, after he was also dismissed late on.
Lens, runners-up in Ligue 1 behind PSG last season, qualified for this match by winning their first ever French Cup with a 3-1 final win over Nice.
PSG coach Luis Enrique named a strong side, making just three changes to the team which won the Super Cup, including giving Lucas Digne his second debut after the France left-back rejoined the club from Villa.
But Bradley Barcola, widely linked with a possible move to Liverpool, was not in the squad.
DOMINATED POSSESSION
The visitors dominated possession in the opening stages but struggled to create clear-cut chances, with Lens goalkeeper Robin Risser making a comfortable save from Khvicha Kvaratskhelia.
Lens grew into the contest and grabbed a 32nd-minute lead when PSG failed to clear before Thauvin slotted home at the back post from Matthieu Udol's cross-shot.
But Toppmoeller's men were dealt a big blow six minutes before halftime when Antonio was dismissed for a studs-up tackle on Maghnes Akliouche.
PSG almost made the most of their man advantage before the break but Desire Doue's effort from a tight angle bounced off the crossbar.
The European champions continued to labour after the restart, though, and Thauvin flashed a strike wide as Lens continued to threaten on the counter.
PSG substitute Mendes came close to an equaliser, drilling a dipping long-range shot narrowly over the bar.
Luis Enrique also brought on Fabian Ruiz and Ousmane Dembele off the bench, with the latter drawing another simple save from Risser.
PSG were reduced to 10 men themselves with three minutes remaining, as Mendes was shown a straight red card for elbowing Lens wing-back Michal Skoras in the face off the ball.