The visitors took the lead in the 17th minute on a stunning volley from Yusuf Yazici, which was followed by goals from Jonathan Bamba just before halftime and defender Tiago Djalo midway through the second half. Six minutes from the end, Cyrille Bayala had given Ajaccio a point after Lille had failed to clear a corner.
Lille, who won the championship in 2021, is in fourth place with seven points, two points behind leaders Paris Saint-Germain, who will play against AS Monaco on Sunday. Ajaccio is in last place with one point and has yet to win since their return to the top flight following relegation in 2014. After receiving a 7-1 home beating at the hands of champions PSG last Sunday, Lille's late penalty attempt by Jonathan David hit the post and prevented them from scoring a fourth.