Lens's difficult start to the new season continued on Saturday as Mamadou Kone scored his first Ligue 1 goal to give Lorient a 1-0 win at last season's runners-up.
After Lens sold several key players and lost their coach in the close season, new boss Dino Toppmoeller started brightly by beating Paris Saint-Germain in the Champions' Trophy and then opening the Ligue 1 campaign with a 5-2 win over Auxerre.
But that was followed by a defeat at Strasbourg and now this second consecutive reverse.
Kone pounced on a loose ball on 54 minutes to score the only goal of the game.
Ahead of their trip to Slavia Prague for a Champions League game on Thursday, Lens showed little fight against an abrasive Lorient.
Monaco top Ligue 1 after snatching a 2-1 win at PSG on Friday, leaving the champions winless so far.
Lens led Ligue 1 for much of last season before finishing just six points behind PSG and winning the French Cup.
In the late games, Ivory Coast forward Elye Wahi snatched a point for Nice in a 1-1 draw at home to Le Mans, while Mali midfielder Kamory Doumbia notched a brace as Brest won 2-1 at 10-man Le Havre, who had Junior Mwanga dismissed.