Saif-Eddine Khaoui’s late winner sank Nice as newly promoted Troyes secured a shock 2-1 win against the Champions League hopefuls.
Tunisian midfielder Khaoui struck the decisive goal in the 85th minute after Alassane Plea’s second-half penalty appeared to have rescued a point for Nice by cancelling out Adama Niane’s brilliant strike for the visitors.
Nice, who travel to Napoli on Tuesday for the first leg of their Champions League second-round qualifying tie, are left waiting for their first league points after last week’s opening-day defeat at St Etienne.
Troyes, who drew their opening game last week at home against Rennes, took the lead in style through Niane’s thunderbolt eight minutes into the second period.
Plea equalised from the spot 10 minutes later after Oswaldo Vizcarrondo’s foul on Pierre Lees-Melou, but Khaoui steered home the winner after being set up by Niane.
For Olympique Lyonnais, Dominican striker Mariano Diaz scored in their 2-0 win at Stade Rennais to take his tally to three goals in two matches and lift his side to top spot.
Memphis Depay opened the scoring with a curling free kick in the 58th minute and Diaz doubled the tally with a header 15 minutes from the whistle.
Benjamin Bourigeaud reduced the arrears in the 86th, but it was too little, too late for Rennes.