Marseille slumped to their second loss in three matches, missing the chance to return to the top of the Ligue 1 table on Sunday.
Elie Baup's side went down 1-0 to lowly Troyes, who grabbed their first win of the season courtesy of Benjamin Nivet's 89th-minute goal.
The loss away from home leaves Marseille second with 19 points, behind the unbeaten Paris Saint-Germain on goal difference.
Elsewhere, Lyon maintained the pressure on PSG and Marseille with a 1-0 victory at home to Brest.
Bafetimbi Gomis struck the decisive goal in the 57th minute, keeping Lyon third on 18 points.
Earlier, Ajaccio drew 0-0 with Bastia in a heated contest that saw both teams finish with 10 men.
Ajaccio's Johan Cavalli and Bastia's Gael Angoula clashed with 10 minutes to go, prompting a melee that spilled over to both benches.
Cavalli and Angoula were both sent off, with referee Laurent Duhamel forced to halt proceedings as fighting broke out in the stands.
The game resumed after appeals for calm and was played out without further incident.