And this weekend, the F1 unknown's profile is so low one would be forgiven for not noticing he is even in Barcelona.
"He's studying and observing," Ferrari president Luca di Montezemolo, in the usual spotlight that follows his rare appearance at grands prix, said in Spain.
Montezemolo has vowed to stick close to Mattiacci while the Italian settles in.
"I'm not happy with our situation," the high-profile president is quoted by Spain's El Confidencial.
"I want to be close to the team and Mattiacci, who has just arrived.
"It was the same for 4 or 5 months when Jean Todt came to Ferrari in 1992, because he was not an expert. Now I want to do the same," Montezemolo said.
Pedro de la Rosa, Ferrari's wise and highly-experienced reserve driver, backed Mattiacci's low-profile transitionary phase.
"F1 is not like football where one person can transform the game," he is quoted by Marca sports newspaper.
Paddock insiders have also reported that Mattiacci already seems much closer to the uncomplicated Kimi Raikkonen than the highly political Fernando Alonso.
But Alonso, who scarcely referred to his new boss by name only three weeks ago in China, now seems open to working with the 43-year-old former Ferrari North America chief.
"Marco has little racing experience," he said, "but plenty on the management side.
"He is listening and learning as fast as possible. We've had meetings to help in all areas and he wants to listen to everybody.
"I don't think he wants to become an engineer, but his priority is to take his time and then make decisions. He needs more time," Alonso added.