Evian's smash-and-grab raid dragged them away from danger and ended Lille's fine run of form to dent their European hopes.
Lille struck a post and missed a penalty as Evian came from behind for an unlikely win against a team who had won five games in a row.
Salomon Kalou put Lille ahead after just seven minutes, but after Dimitri Payet hit the upright, Saber Khlifa levelled on the half-hour mark, and Kalou then scored an own goal in the 67th minute before missing a spot-kick.
Lille's outstanding vein of form had seen them move firmly back into the European picture, and everything appeared to be going to plan when Djibril Sidibe crossed for Kalou to finish on the volley after seven minutes.
They were given a warning sign when Steeve Elana made a difficult save to turn Khlifa's volley away for a corner in the 25th minute, but thought they had a second moments later when Payet's curling free-kick came back off the post.
It proved costly, as three minutes later Khlifa had Evian level, linking up with Cedric Barbosa to break into the area and slot the ball past Elana.
Lille started the second half determined to regain the lead, but Bertrand Laquait did well to punch Payet's shot away moments after the restart and then denying Kalou after the Ivorian latched on to Payet's long ball.
Everything would go wrong for Kalou late in the game, as he first got an inadvertant touch on Djakaridja Kone's header to turn it into the net, and seven minutes later he sent a penalty over the crossbar after Kone brought him down in the area.
Evian hung on for a big morale-boosting win, their second in a row and first on their travels since November.