"I'm only learning this now," the visibly stunned coach revealed. "I cannot say anything else other than I always got on so well with him. I'm tied to him in a sporting sense but also emotionally."
Indeed, it was Marotta who had pushed for Allegri's appointment as Juve boss in 2014 in spite of strong opposition among the supporters. The former AC Milan coach was even pelted with eggs upon his arrival in Turin.
Marotta, though, was adamant that Allegri was the right man to succeed Antonio Conte at the helm - and he wasn't wrong. He rarely is.
During his eight-year spell with Juventus, Marotta established himself as arguably the shrewdest operator in the transfer market in world football. Without him, the Bianconeri's rebirth simply would not have happened.
Arriving from Sampdoria in the summer of 2010 – with Fabio Paritici in tow - Marotta endured a trying first season in Turin before ushering in an unprecedented period of sustained success: seven successive Scudetti, and four consecutive domestic doubles. And counting.
There were some expensive flops during the early days – Milos Krasic for one – but it was Marotta’s signings who transformed a club still feeling the effects of Calcipoli into the most dominant team Serie A has ever seen.
He picked up Andrea Pirlo, Paul Pogba, Sami Khedira, Fernando Llorente and Patrice Evra for nothing, and acquired Andrea Barzagli for just €300,000. Stephan Lichtsteiner, Arturo Vidal and Carlos Tevez were brought in for roughly €10 million apiece.
Even Paratici was continually left in awe of his long-time colleague’s transfer market acumen: "Working with Marotta is like being at Harvard. You keep learning every day."
However, when it came to the biggest and most significant deal in Juve’s history, Paratici, with the backing of president Andrea Agnelli of vice-president Pavel Nedved, was willing to disregard the opinion of his mentor, thus precipitating the end of Marotta’s time in Turin.
Marotta was against the €100m signing of Cristiano Ronaldo – not from a sporting perspective but a financial one.
Marotta had been preaching a more conservative approach to the market for some time. However, Agnelli wanted a statement signing, a transfer that would rubberstamp Juve's status as major players on the European scene.
When Marotta learned during negotiations with agent Jorge Mendes over the signing of Joao Cancelo that Ronaldo was also available, Agnelli knew his moment had arrived and both he and Nedved advised the equally enthusiastic Paratici to pursue the Portuguese at all costs.
Unsurprisingly, Marotta, a man renowned for his frugality, was perturbed by the prospect of jeopardising the club’s financial stability by putting together an estimated €360m package (including wages) for a 33-year-old.
Agnelli and Paratici, though, were looking at the bigger picture, feeling that Ronaldo – with his colossal commercial pulling power – would transform Juventus into a truly global brand.
With the benefit of hindsight, it now looks significant that when Ronaldo was unveiled as a Juventus player at the end of July, the No.7 was flanked by Agnelli and Paratici, with Marotta literally consigned to the fringes.
Still, it must be said that the tension between Marotta and Agnelli had been mounting long before the Ronaldo deal. They had been at odds with one another over various issues, including the club's medical staff.
Thus, Ronaldo’s arrival wasn't wholly responsible for Marotta's exit; it was merely the tipping point, a glaringly obvious illustration of the fact that he and his colleagues were, as he put it, “no longer in sync”.
There was no bitterness on his part either: "It's what the club want and there wasn't one particular thing which sparked it. I just align myself with their ideas and directives, for my love of the people and of Juventus.
"If Juve reach the final of the Champions League, I would be happy because it would also be the fruit of my work and that of my assistants. If they go all the way, I will be there to support them as a fan."
At Vinovo, too, there is a profound respect for Marotta's role in Juve's re-emergence, and not only because of his dealings in the transfer market. Marotta also played a pivotal part in Agnelli – who was just 34 when he took control of Juventus – developing into one of the most astute and influential presidents in football.
As a result of his exit, though, Marotta himself suddenly became one of the hottest properties on the market. There was talk of a run for the presidency of the Italian Football Federation (FIGC) but he wanted to remain in club football.
With Manchester United boss Jose Mourinho under intense pressure at the time, he was linked with a reunion with Conte at Old Trafford.
However, Marotta was drawn to Juve's great rivals Inter – and vice versa.
Just as Juve were a fallen giant in 2010, so Inter are a great club struggling to reassert themselves among the game’s elite, one renowned for their failings in the transfer market.
They are also handicapped by budgetary constraints – they were unable to sign either Cancelo or Rafinha last summer because of their struggles to meet UEFA's Financial Fair Play (FFP) regulations – meaning Marotta's nose for a bargain would thus be most welcome at San Siro.
Furthermore, Inter are in better shape than Juve were when Marotta first arrived in Turin.
Luciano Spalletti's improving side secured a return to the Champions League this season and boast a decent squad with a smattering of world-class performers, including captain Mauro Icardi, in-demand defender Milan Skriniar, Dutch centre-half Stefan de Vrij and Croatian World cup stars Ivan Perisic and Marcelo Brozovic.
With a few big signings – and Inter have already been linked with the likes of Pogba and Sergej Milinkovic-Savic since it became clear that Marotta was bound for San Siro – Inter could well put themselves in a position to mount a credible threat to Juve's Serie A supremacy.
Not that it will be easy, of course. Marotta laid foundations in Turin that will not be easily toppled.
"I believe that the dominance of the Bianconeri can last a long time," he conceded recently. "They have a very strong organizational and technical structure."
The target now, though, will be to replicate that structure, and indeed the success it yielded, in Milan.
Goal understands that his appointment will be made official after next weekend's Champions League meeting with PSV but Marotta will not be returning to Turin on Friday night when Inter take on Juventus in an eagerly awaited Derby d'Italia, thus denying Allegri the chance to catch up with a man to whom he remains deeply indebted.
"I was with him for four-and-a-half years, beautiful and important years,” Allegri enthused. “He's the best director in Italy, perhaps even in Europe.
“He built Juve, together with Paratici, Nedved and the president. He made a very strong squad, winners on and off the field."
Essentially, he put Juve back on their perch. His objective now, though, is to knock them off it.