Super agent Mino Raiola sharply criticized Pep Guardiola in comments to Dutch magazine Quote.
Raiola represents Zlatan Ibrahimovic, Paul Pogba, Romelu Lukaku and others.
"As a manager Guardiola is great, but as a human he's a zero!" he said. "He said we had to talk to him if we had any complaints, but then he stopped playing Zlatan and ignored him. He didn't even greet him.
"Guardiola is like a classic priest: do what I say, don't do what I do. I advised Zlatan to go to work in a Ferrari and to park it in his spot."
Raiola revealed that he almost came to blows with Guardiola when he left out Maxwell for the 2011 Champions League final against Manchester United.
"Guardiola is a cowardly dog," he added. "He pulled the same trick on Maxwell, who is a great guy. I went to London for the Champions League final and saw in the stadium that he wasn't on the list. So that f---ing Guardiola wanted to let [Eric] Abidal make his re-entry [after recovering from liver cancer]. That was fine of course, and you can see why, but be honest about it.
"I was livid, almost went for him [Guardiola] in the catacombs, but luckily Adriano Galliani, AC Milan's president, was able to stop me."