De Zerbi's Marseille continue strong start in Ligue 1
Mason Greenwood was unable to add to his remarkable tally of five goals in his first three matches in French football, but there was a debut goal for new signing Neal Maupay before a brilliant strike by Luis Henrique sealed the victory.
Marseille had Canadian defender Derek Cornelius sent off late on, but held on for the win which moved them to 10 points from four matches.
That lifted them a point clear of Paris Saint-Germain, although the defending champions will return to the summit if they can maintain their perfect start to the campaign by beating Brest later.
The game at the Velodrome was watched by a crowd of more than 65,000 and there was a celebratory atmosphere as Marseille wore a collectors' edition shirt to mark their 125th birthday and fans set off fireworks late on, bringing the game to a brief halt.
Maupay opened the scoring five minutes before half-time in this Mediterranean derby when he headed in a deflected cross by Luis Henrique for his first goal since returning to French football from Everton.
Luis Henrique, the Brazilian winger, made it 2-0 with a magnificent goal eight minutes into the second half as he came in off the left flank and played a quick exchange with Amine Harit before curling a shot high into the net.
Cornelius was dismissed for a second yellow late on 75 minutes, but that did not stop OM getting all three points, and hopes will be high that they can push PSG in the title race if they can keep playing like this.