De Zerbi had essentially failed to figure out the cause of his side's schizophrenia. One week, they looked like potential world-beaters; the next, completely clueless.
"I'd like to understand why, here in Marseille, we systematically experience these rollercoaster rides, these ups and downs," De Zerbi said after a particularly frustrating loss at home to Nantes on January 4. "This is my 12th season as a coach, but today you have to be more of a psychologist than a coach." The latter is most definitely a role to which De Zerbi is unsuited.
He may be meticulous in his approach to games, but he's rarely - if ever - calm, cool and collected, particularly when dealing with players. Indeed, it's quite telling that while comparing De Zerbi to Klopp, former Liverpool winger Adam Lallana revealed that he often had to tell his team-mates at Brighton not to take the things that were being said to them on the training pitch to heart. "Don't worry," he'd say, "it's coming from a good place."
De Zerbi's will to win certainly can't be questioned and his intensity is part of what makes his teams so watchable, but the overriding impression is of someone who hasn't yet got the balance right between passion and composure. In that context, he's a bit like Antonio Conte - but without the league titles. And that lack of success is why many people are growing increasingly critical of De Zerbi and his methods.
"Self-esteem is a quality, but here we are dealing with a huge ego," former Marseille and France forward Christophe Dugarry told RMC Sport. "He coached Sassuolo and Brighton, but he speaks as if he's won two Champions Leagues."
After having such high hopes for De Zerbi when he arrived at the Velodrome, Dugarry now believes that the 46-year-old has turned out to be "overrated", a "mediocre coach" and poor man-manager who struggles to impact games with his substitutions.
Of course, such a scathing review is unlikely to prevent De Zerbi from getting another job soon. He actually left the Velodrome with the best win percentage (57) of any Marseille manager since the turn of the century, while Pierre-Emerick Aubameyang was among several players to pay tribute to the Italian. "From experience, I know that you don't find a coach like you every day," the veteran striker wrote on social media.
De Zerbi is certainly a rare breed, a unique character with an ability to get teams playing aesthetically pleasing football - and fast. For that reason, he still has plenty of admirers in Italy and England, and is likely on Tottenham's shortlist to succeed Thomas Frank as manager.
However, if his time in Marseille has taught us anything, it's that wherever he goes next, it likely won't be for long.