With Chris Smalling and Phil Jones both sidelined by long-term injuries, Rafael has emerged as United's first-choice right-back this season.
The 22-year-old has responded with a series of decent performances, and a couple of very important goals, the latest at Liverpool last weekend.
However, the Brazilian, who featured in his country's silver medal-winning Olympic squad at London 2012, retains an impetuous streak which takes Ferdinand back to his own youth.
"Rafa is his own worst critic," said Ferdinand.
"He is emotional and sometimes when he makes a mistake he has to make up for it immediately. That comes out in his game at times.
"When I was his age I was a lot like that.
"I used to be more interested in what was happening in the attacking part of the game and further up the pitch than defensive play.
"With experience that will disappear and you will see a top right-back."
As Ferdinand recalls, he did not fully appreciate the art of defending until he started receiving guidance from David O'Leary following his move to Leeds in November 2000.
"I realised it when I went to Leeds at 22. I was more of a maverick under Harry Redknapp at West Ham and when I went to Leeds David O'Leary pulled the reins in and made me think about my defensive duties first.
"He said everything else would come naturally.
"I speak to Rafa about it similarly and he's a quick learner."
Ferdinand's name is back in the headlines again as a potential England player following John Terry's decision to abandon the Three Lions.
It is not known whether Roy Hodgson will now consider the 33-year-old, who he left out of Euro 2012 for "footballing reasons".
Ferdinand's performance at Anfield on Sunday suggests he is still capable of operating at the highest level, even if Sir Alex Ferguson will want him wrapping in cotton wool following confirmation skipper Nemanja Vidic will be out for another eight weeks with a knee injury.
For his part, though the former West Ham man has never said his international career was over, privately he has felt that way.
And even now he just wants to focus on matters at Old Trafford.
"Personal performances and accolades come way down the list when you are winning at places like Anfield," he said.
"I have always said I just want a consistent run of games. At the moment that is what I am doing and I am really happy."