Metz scored twice in the last 10 minutes to beat Lyon 2-1 as the once dominant team in French football continued their early-season struggle.
Alexandre Lacazette gave Lyon the lead midway through the second half, but a penalty from Yeni Ngbakoto levelled up and Juan Manuel Falcon poached a late winner for the home side.
Visitors Lyon, who have now lost three on the trot after starting with a win over Rennes, began the brighter and Corentin Tolisso showed his intentions early with an effort from long distance that failed to test Johann Carrasso in the hosts' goal.
Lyon continued to dominate early proceedings and a lapse in the Metz defence gifted Clinton Njie with a great opportunity but the youngster shot straight at Carrasso.
In a rare chance for the hosts, Jeremy Choplin neatly picked out Ngbakoto but his acrobatic effort sailed over the bar.
The game began to open up as the first half came towards its close and Lyon had claims for a penalty turned down after Rachid Ghezzal burst into the area before taking a tumble. Referee Ruddy Buquet showed no interest.
The visitors went close to breaking the deadlock just before the interval when Lacazette's shot took a wicked deflection to loop over Carrasso but the Metz goalkeeper recovered brilliantly to tip the ball onto the bar.
Metz began the second half with greater impetus but struggled to break down a resolute Lyon defence.
The hosts had their own penalty claim after the hour mark when Romain Rocchi was barged over inside the area but yet again Buquet waved play on and Lyon made them pay.
Hubert Fournier's men counter-attacked with great effect and Ghezzal saw his initial shot parried by Carrasso but Lacazette was on hand to stroke the ball home.
Metz offered an immediate response and Kevin Lejeune drew a decent save from Anthony Lopes direct from a free-kick before the hosts completely turned the game on its head.
With less than 10 minutes to play, Jordan Ferri stuck a high boot on Bouna Sarr inside the area to concede a penalty. Ngbakoto took charge from 12 yards, firing a confident finish beyond the diving Lopes.
Then, as the full-time whistle approached, Lejeune saw his cross fortuitously deflected into the path of Falcon who beat Lopes with a diving header to claim an unexpected three points for Albert Cartier's men.