Benjamin Nivet gave Troyes' chances of avoiding the drop from Ligue 1 a massive boost when he scored an injury time winner against champions Lyon.
Club captain Nivet slotted in from close range four minutes into injury time, to secure a memorable victory for a Troyes side very much still involved in a battle to beat the drop.
Lyon have struggled this year for form and have now seen their lead at the summit cut to 11 points with 15 games remaining, following what was their third defeat in five league matches.
Troyes goalkeeper Ronan Le Crom had a fine game between the posts for his side, with two excellent stops denying trademark Juninho free-kicks, while in the final minute Lyon striker Hatem Ben Arfa was thwarted by a brave save at his feet.
In Sunday night's other clash Marseille and Paris Saint Germain could not be separated in a hard fought 1-1 stalemate.
Marseille took the lead on home soil when in-form Djibril Cisse broke the deadlock in the 68th minute but it would prove to be a short-lived advantage as Pedro Pauleta soon struck back for PSG.