Second-half goals from
Gignac opened the scoring in the 54th minute and Fanni netted a stoppage-time second as Marseille followed up its 1-0 victory over Reims last time out with another triumph that leaves it level on points with the Ligue 1 pacesetters.
The home side had to wait until the second half to finally make the breakthrough, with Gignac winning an aerial duel with Mathieu Peybernes to power a header beyond Cros and give Marseille a deserved lead.
But Marseille was unable to finish game off until the 90th minute when Fanni poked home from close range off the underside of the bar to make it 2-0.
Ludovic Obraniak scored the only goal as Bordeaux also picked up a second victory.
Having missed a penalty in the first half, the home side finally broke the deadlock when Obraniak ended a goalmouth scramble in the 75th minute by firing past goalkeeper
Rennes pressed for a late equaliser but could not find a way through, with
The visitor had
Ajaccio was well organised and stubborn at the back, limiting the away side to few chances.
Marseille president Vincent Labrune has described newly-promoted Monaco as a 'foreign club' and warned the Ligue 2 champion it must obey new rules relating to tax if it wants to be welcomed into the top flight.