Marseille piled more pressure on Chelsea's under-fire boss Carlo Ancelotti as a second-half goal from Brandao was enough to bring their unbeaten Champions League run to an end.
Having already won Group F, the Blues were lethargic and passionless despite Ancelotti's call for a return to the free-flowing football they produced at the start of the season.
Although the game had nothing riding on it apart from pride, the English champions looked a shadow of the side that took defences apart with ease last season.
The Blues have now recorded just two wins out of their last eight games in all competitions and the storm clouds will continue to gather over Ancelotti until they reverse their alarming slump.
Marseille started brightly and almost took the lead in the seventh minute, but Benoit Cheyrou's volley from 20-yards flashed just wide of the post.
It certainly was not the entertaining start Carlo Ancelotti had wanted from his side.
In the 10th minute only the woodwork saved Chelsea when Mathieu Valbuena rattled the crossbar with a 20-yard drive that had Petr Cech beaten.
Moments later Loic Remy flashed another long-rage effort just wide and Brandao put another shot on the turn inches wide of the upright as Chelsea looked extremely vulnerable in defence.
In the 15th minute there was total confusion when Chelsea appeared to have been awarded a penalty by Russian referee Vladislav Bezborodov after Souleymane Diawara brought down Florent Malouda.
The Russian pointed to the spot but, under pressure from Marseille players, appeared to consult his linesman and change his mind.
He then awarded the Blues a corner instead, much to the annoyance of the Chelsea players.
Ancelotti's side had rarely ventured into the home penalty area and Ramires opted for the long-range approach in the 21st minute, though his effort was far too high.
A clever move involving Malouda and Michael Essien finally allowed Didier Drogba the freedom to shoot but the Ivorian, clearly still not back to his best, missed the target.
Marseille had a goal ruled out for offside in the 35th minute when Gabriel Heinze was adjudged to have slipped offside from Cheyrou's free-kick.
Heinze rose unchallenged to head home from six yards but was immediately flagged offside by the referee's assistant.
In the 43rd minute Salomon Kalou burst into the Marseille penalty area but his shot was high and wide.
Chelsea began the second half in the same lethargic fashion as they ended the first period.
It was the home side who again looked the more threatening but although they pinned Chelsea down in their own half, the final ball was lacking.
Drogba, who had looked distinctly out of sorts all evening, was eventually replaced on the hour by Daniel Sturridge.
The former Marseille goal hero was given a standing ovation from the home fans as he walked off the pitch.
Goalmouth incidents were increasingly rare in a game that had little riding on it but Taye Taiwo almost sparked the contest into life in the 64th minute when his shot flashed past the far post.
Two minutes later a cross from Taiwo was saved by Cech as substitute Lucho Gonzalez looked to pounce.
The deadlock was broken in the 81st minute when Taiwo's cross-shot was deflected into the patch of Brandao by Ramires and the Marseille tucked the ball home from six yards.
It was a killer blow for Ancelotti who had watched another insipid performance from his players and looked distinctly unhappy as he left the pitch.