'Magical' Dembele brace fires Paris Saint-Germain top in France
Surprise packages Lens could return to the summit on Saturday should they win at Auxerre, but PSG coach Luis Enrique will be buoyed by a return to form from his top striker.
Dembele won the Ballon d'Or last season but has suffered an injury-blighted season so far.
His goals, including a stunning lob, on Friday will hearten the PSG faithful, however.
A confident Dembele curled a sweet left-footed shot into the bottom corner from outside the box on 13 minutes to open the scoring.
He then chipped Lille goalkeeper Berke Ozer from inside the box for a sumptuous second just after the hour mark.
"That's the magic of Ousmane, he can do anything, he's just brilliant," said teammate Warren Zaire-Emery after the game.
He also netted shortly after the break, popping up unmarked at the far post only for an offside flag to deny him.
Bradley Barcola, a late substitute for an industrious but misfiring Khvicha Kvaratskhelia, clipped home the third in stoppage time, pouncing on a defensive mix-up that left him with only Ozer to beat.
PSG goalkeeper Lucas Chevalier had little to deal with over the 90 minutes.
Fourth-placed Lille harried PSG into spilling several loose balls, one of which offered a half-chance to veteran Olivier Giroud, who chipped the ball onto the bar for an agonising near miss when they were only 1-0 down.
PSG started with Dembele, Desire Doue and Kvaratskhelia in a line up similar to the one that beat Inter Milan in the Champions League final last May, but were missing key defender Achraf Hakimi, who will play in the African Cup of Nations final for Morocco on Sunday.
The Parisians won the league by 19 points last season but Lens have strung together a nine-match winning run in all competitions to keep pace with the European champions this season.