Lille grabbed top spot in Ligue 1 on Sunday by thrashing newly-promoted Lens 4-0 in France's northern derby as the ill-disciplined visitors had two players sent off.
Lens had a chance to go top in France for the first time in 16 years but their defensive frailties were ruthlessly exposed by Lille who move two points ahead of defending champions Paris Saint-Germain.
Burak Yilmaz's low shot put the home side ahead in the echoing, empty Stade Metropole after 11 minutes.
Lens hung on till the second half when Jonathan Bamba scored Lille's second before first Jonathan Gradit and then substitute Clement Michelin were shown red cards as Lens fell apart.
Jonathan Ikone and Yusuf Yazici completed the job for Lille.