The Hoops have averaged a point a game since Redknapp took charge immediately after their first meeting with United at Old Trafford in November.
Yet it is a measure of the perilous situation they were in before Redknapp was installed as Mark Hughes' successor that they remain four points adrift of Wigan at the bottom of the table - and more importantly seven behind Aston Villa, who sit just above the relegation zone.
Given the massive investment owner Tony Fernandes made, both getting Redknapp to Loftus Road and then bringing in even more players in the last year, it looks like a lavish outlay is about to backfire badly.
Ferguson realises he can make the problems even more acute this weekend.
However, he is convinced if anyone can drag Rangers out of the mire it is his old friend Redknapp.
"It is not easy when you are down at the bottom of the league," said Ferguson. "Harry will be the first to admit that.
"It may have helped him if he had gone a bit earlier. But with Harry's experience and ability to judge players, he will have a better chance that most in that situation."
Concern has been expressed about the money Fernandes spent during the January transfer window attempting to secure survival.
Loic Remy was snapped up in an £8million deal just as it seemed he was about to join Newcastle.
Former Blackburn defender Christopher Samba cost even more after a brief spell with big-spending Russian outfit Anzhi Makhachkala, whilst ex-England midfielder Jermaine Jenas made the short journey from Tottenham.
Other moves for Peter Crouch, Scott Parker and, memorably, Peter Odemwingie failed in an approach that looked little more than panic buying.
And all, Ferguson believes, because the fear of what exists outside the cosy confines of the Premier League haunts those within the elite.
"You can't make money in the Championship," said Ferguson.
"You get the parachute payments, which are terrific I suppose.
"I don't see why it should apply itself but it is there and teams can benefit from that.
"But player contracts are an issue because some of them are on very good ones and the clubs have to pay them.
"If you drop down, I would imagine motivation is very difficult.
"The only place you want to be is the Premier League. That is reflected in QPR spending the money they have."
The task facing QPR is to halt the slide immediately or risk tumbling into near oblivion.
Clearly, these are not concerns to bother Ferguson.
His only task this weekend is to engineer a victory in west London that would put United 15 points clear at the top of the standings 24 hours before closest challengers Manchester City take on Chelsea at the Etihad Stadium.