The loss left Lille in 10th place ahead of hosting German Bundesliga highflyers Wolfsburg in their Champions League opener next week.
It also ended their fine 10-month run without a loss on the road.
"It's an unacceptable defeat," Lille central defender Jose Fonte told Prime Video. "We have to do better, show more determination."
Moffi, 22, provided the assist for Armand Lauriente to give the hosts an early edge.
Turkish veteran Burak Yilmaz had Lille back level from the penalty spot on 25 minutes after minor contact with Julien Laporte.
With the game heading for a draw Vincent Le Goff picked out the tireless Moffi who escaped his two markers to secure the winner in rhe 86th minute.