In an entertaining opening half, Said found the back of the net either side of Nicolas de Preville's goal for Metz before Ignatius Ganago and Przemyslaw Frankowski struck late to put the Sang et Or on 21 points from 11 games.
They trail leaders Paris St Germain, who travel to Olympique de Marseille later on Sunday, by six points.
Nice, who briefly occupied the second spot after a sensational 3-2 comeback win over Olympique Lyonnais, are third with 19 points and a game in hand.
Said put Lens ahead in the 15th minute with a powerful shot that bounced in front of keeper Alexandre Oukidja.
Metz, who are 19th on six points, responded in the 33rd as De Preville netted from 20 metres after keeper Jean-Louis Leca and defender Jonathan Gradit found themselves on the ground after clashing at a corner.
Said, however, restored the advantage for the hosts from point-blank range from Florian Sotoca's cross eight minutes before the break.
Metz piled on pressure in the second half but Leca was vigilant and Ganago put the result beyond doubt by wrongfooting Oukidja with a low shot seven minutes from time.
Frankowski added the fourth in the last minute as he tapped in from Jonathan Clauss's well-delivered cross.