This season, the German tactician has taken over for Ole Gunnar Solskjaer at Manchester United and has largely delivered positive results since taking over at Old Trafford in January.
Ferdinand, on the other hand, is still concerned about the inconsistent nature of this team, describing the Red Devils as "like Jekyll and Hyde" under Rangnick, despite the fact that this was also the case for much of Solskjaer's tenure.
It's going to be a big week for Manchester United. They're going to play Atletico Madrid in the Champions League this week, and they want to keep up their good form from the 3-2 win over Tottenham on Saturday.
Ferdinand, on the other hand, says it's frightening how much of an issue this team has with maintaining consistency, which could make some MUFC supporters apprehensive ahead of such a crucial encounter as tomorrow night's clash with Manchester United.
According to Ferdinand, who spoke to the Daily Mirror, "the results have been generally positive – but you have to keep in mind the calibre of opponents."
It has been incredibly fortunate for him in terms of the clubs he has faced, their caliber and position in the league.
Continue to pay attention.
"The main source of concern for him, and what has perhaps startled him the most, is the mixture of Jekyll and Hyde performances that he witnesses inside the first 90 minutes.
Since his debut game against Crystal Palace, I don't think I've ever witnessed a game in which he performed consistently throughout.
No other match has come along when you believe they have been truly outstanding for 90 minutes - when you believe they have put in a solid performance where you believe they are in complete command."
As far as he is concerned, "you are not looking for flamboyant performances, but one where there is soundness - that is probably the main concern for him beyond particular players."
Wisdom Nnebi 4 d
Very okay