Burak Yilmaz and Mehmet Zeki Celik struck after the break to give Lille a 2-0 win at Metz as the northerners opened a provisional six-point gap at top of the Ligue 1 standings on Friday.
The Turkish duo put Lille on 69 points from 32 games, with second-placed Paris St Germain playing their match in hand at Racing Strasbourg on Saturday.
Christophe Galtier's side, who beat PSG 1-0 at the Parc des Princes last weekend, had Mike Maignan to thank for as the keeper saved a first-half penalty and made decisive saves.
Yilmaz on fire as Lille edge closer to title with Lens win
Metz are 10th on 42 points, seven points behind fellow promoted RC Lens who occupy the last Europa League qualifying spot.
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Yilmaz and Celik strike as Lille stay on title track