Nantes missed the chance to go top of Ligue 1 on Friday after Ludovic Ajorque's last-minute penalty saw Strasbourg come from behind to win their first match of the season 2-1.
Ajorque struck from the spot after Jean-Ricner Bellegarde was brought down in the area, capping a powerful second-half display that also featured a smart Dimitri Lienard leveller in the 66th minute and moved Strasbourg out of the relegation zone.
The defeat means Nantes failed to leapfrog league leaders Paris Saint-Germain despite taking the lead with a fine Kalifa Coulibaly strike midway through the first half.
"We had some good moments in the first half... but in the second half Strasbourg had to react and we couldn't get out and keep the ball up against their pressing," said Nantes coach Christian Gourcuff.
"The late goal is difficult to digest. We had the game by the scruff of the neck but what we showed wasn't good enough."
Nantes drop down to fourth and stay two points behind PSG, who travel to Lyon on Sunday, level on 10 with Rennes and Marseille.
Thierry Laurey's Strasbourg meanwhile move up to 13th with the win.