It was the second consecutive home defeat at the Velodrome for OM.
Afterwards, former Brighton manager De Zerbi snapped: "If I'm the problem, I'm ready to leave.
"I come from the streets, I'm direct, I don't talk for the sake of talking. I told Medhi Benatia (sports director) and Pablo Longoria (president): 'if I'm the problem, I'm ready to go. I'll leave the money and return my contract'."
The Italian continued, "I came to Marseille for the Velodrome, to play at the Velodrome. I can't get the players to give what I see in training and outside. So it's my fault, it's my responsibility."
Interviewed a few minutes later in the mixed zone, Marseille captain Leonardo Balerdi defended the coach.
"Is the coach the problem? No, it's not him. We, the players, have to take our responsibilities. He commits and gives his heart, we have to put more in to turn the page," said the Argentine defender.