Marseille capped Michel's first game in charge of the club by picking up their first league victory of the season against Troyes.
OM, who were without a point and saw Marcelo Bielsa resign on the opening weekend of the season, went ahead on 19 minutes when Michy Batshuayi's shot beat Denis Petric, but came back off the crossbar before Abdelaziz Barrada tucked home the rebound from close range.
Barrada nearly scored Les Olympiens' second midway through the opening period, but Petric was alert enough to keep out the midfielder's attempt.
Marseille did double their advantage moments after the interval when summer signing Lassana Diarra's shot from the edge of the box found the top corner of the net.
Batshuayi wrapped up victory for OM before the hour mark when he was teed up by Remy Cabella before stroking low past Petric.
Four minutes later, Marseille scored a fourth as Lucas Ocampos, moments after coming on as a substitute, rifled the ball into the top left corner.
With time running out, Romain Alessandrini made it five before turning provider for Batshuayi's second of the evening in the final minute.