The Juventus director has hailed the motivational skills of the former Siena boss after the Turin giants won their third straight Serie A title
Roma's 4-1 defeat to Catania on Sunday ensured that the Bianconeri retained their title regardless of their result against Atalanta, whom they eventually beat 1-0 on Monday.
And Marotta is in no doubt as to who was behind their success in recent years.
"It's an extraordinary and unique achievement," he told the club's official site.
"The credit must certainly go to the coach, who, aside from his technical and professional abilities, is a magnificent leader of the group and has instilled a winning mentality since his first day.
"We’re proud of our coach who I regard as one of the best in the world, not just because of his important footballing principles, but also for the way he’s able to manage and motivate the squad.
"We said and knew that it would be a difficult season, but we were able to count on a superb coach and team who had great hunger and motivation to achieve this third title."