As exclusively revealed on Wednesday, Sir Alex hand-picked David Moyes as his successor, who was unveiled on Thursday, after a 26-year reign filled with titles and trophies.
Ancelotti did the double over Sir Alex during Chelsea’s league and cup double in the 2009-10 season, and revealed they always got on well off the pitch.
"He's a symbol, a legend and a hero for Manchester United," the Italian wrote in a column for La Gazzetta dello Sport. "But at the same time he's humble, modest and still has the passion of a child in carrying out his work.
"I don't remember the exact moment I met him for the first time, but I know we hit it off immediately. We were adversaries. At times I won and at times he won, but we were never enemies. At the end of each game we'd enjoy a good glass of wine and a laugh. This is the kind of football I like, and that Sir Alex likes as well."
Ancelotti hinted that Sir Alex's longevity has been down to a good relationship with the club's owners and chiefs; something which has brought great success in an era of swift managerial changes.
"No director or president has ever questioned him," he added. "This should be a lesson to those in the world of football, since far too often you find a lack of patience in this environment. Coaches need time to convey their thoughts, to make themselves understood and to give shape to their ideas of the game. Sir Alex had this time."
Moyes clearly has big shoes to fill, but Ancelotti believes the new Red Devils manager simply needs to carry on where his predecessor left off.
"For us coaches, Ferguson's adventure is a model to be followed," he continued. "I think his greatest achievement was transmitting a sense of belonging to the players he guided. Being a part of Manchester United, being a Red Devil, is something that will never fade.
"For once a withdrawn and simple man like him will accept the plaudits. In the end, they're justified. And most importantly, he deserves them."
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