Marseille blew the chance to return to top spot in Ligue 1 in spectacular fashion as Lorient ran out comfortable winners at Stade Velodrome.
OM have endured a torrid time on home soil in recent weeks, with today's drubbing coming just a fortnight after they shipped four goals in a damaging defeat to title rivals Lyon.
The Stade Velodrome was enveloped in gloom once more today as goals from Jeremie Aliadiere, Benjamin Corgnet and Kevin Monnet-Paquet condemned the Mediterranean club to defeat, with the fans turning their ire against club president Vincent Labrune at the final whistle.
Marseille were hampered by the 38th-minute dismissal of Charles Kabore for the foul that led to Aliadiere opening the scoring from the penalty spot, but even before that turning point the hosts had hardly appeared poised to take the game to a team with just one win in nine prior to kick-off.
Marseille came into the game aware that victory would provisionally take them top ahead of Lyon's encounter with St Etienne later on Sunday night, and they carved out the first chance in the seventh minute when Loic Remy's volley drew a good save from Fabien Audard.
It was Lorient who looked more threatening for the remainder of the half, however, and seven minutes before the break they turned their promise into the lead when Kabore received a second yellow card for a foul in the area on Aliadiere, who picked himself up to stroke home the penalty beyond Steve Mandanda.
Marseille's hopes took a further nosedive on 47 minutes when a poor clearance by their defence fell to Alain Traore, who threaded the ball through for Corgnet to fire thunderously into the roof of the net.
Mandanda limited the damage when he saved well from Monnet-Paquet in the 61st minute, but the OM goalkeeper had no answer seven minutes later when the same player fired the ball low beyond his grasp after good work by Aliadiere.