Rovers took more points off a team chasing the title as fortress Ewood was in full effect once again.
Following on from their 1-1 draw against Chelsea last month, Sam Allardyce's side put a dent in another club as Manchester United struggled to find a way past a determined home side who restricted the visitors to very little in a goalless encounter.
Chris Samba forced the first save of the game when his downward header was saved by Edwin van der Sar as early as the 8th minute.
But the only other chance of note came just before the break when Dimitar Berbatov played Antonio Valencia through on goal, but he couldn't find a way past Paul Robinson who spread himself to make a fantastic save.
Whilst the visitors enjoyed plenty of possession, a resolute Rovers kept them at bay, reducing United to half chances and long range efforts.
Rovers rallied late on but shots from El-Hadji Diouf and Steven Nzonzi saw their efforts blocked.
With Arsenal to come to Ewood next month, Rovers could play an increasingly key role in who wins the Barclays Premier League.
Ahead of the game Sam Allardyce has made three changes from the side that drew a blank against Portsmouth last time out.
Back into the starting eleven came Vince Grella, Brett Emerton and Nikola Kalinić, with David Dunn, El-Hadji Diouf and Jason Roberts dropping to the bench.
The visitors made six changes from the side that were knocked out of the Champions League by Bayern Munich in midweek.
Rovers started brightly and threatened United's goal early on. Paul Robinson thrust an 8th minute free-kick into the area, Grella picked out Chris Samba but his downward header was saved by van der Sar.
With the visitors without Wayne Rooney they lacked any thrust up front and it wasn't until the 25th minute that they threatened the Rovers box. Macheda playing in Valencia down the right, but he chose to shoot from a tight angle which Robinson kept out.
The home side were dealt a blow when Chris Samba had to be substituted with a groin strain, but the fit again Ryan Nelsen was certainly more than able to replace.
Just before the break Paul Robinson made a vital save to keep the scoreline goalless at half-time, racing off his line to spread himself to block a shot from Valencia.
A slight hamstring injury saw Brett Emerton being replaced by David Dunn as the second half got underway, but that reshuffle didn't affect the collective.
With Steven Nzonzi and Vince Grella affording very little space to the United's forward line, the flanks were United's only route to goal, but Nani and Valencia were thwarted time after time by the impressive Gael Givet and Michel Salgado.
On the odd occasion that Manchester United did break through, they found the imperious double act of Phil Jones and Ryan Nelsen to ensure that Paul Robinson was rarely tested.
Yes the visitors enjoyed a lot of the ball, but aside from the odd long-range effort and some scrambles in the area, there was to be no way through.
At the death it could have been Rovers to snatch the points when El-Hadji DIouf and Steven Nzonzi both saw great chances blocked, but Sam Allardyce will have been delighted with another clean sheet and another important point.
ROVERS: Robinson, Salgado, Samba (c) (sub Nelsen 33 mins), Jones, Givet, Emerton (sub Dunn 46 mins), Grella, Nzonzi, Pedersen, Olsson (sub Diouf 71 mins), Kalinić.
Subs not used: Brown (GK), Roberts, Andrews, Di Santo.
MAN UTD: Van der Sar, Neville (c), Ferdinand, Berbatov, Giggs (sub Gibson 58 mins), Vidic, Nani, Scholes, O'Shea (sub Evra 79 mins), Valencia, Macheda (sub Park 65 mins).
Subs not used: Kuszczak, Evans, Fletcher, Obertan.
Booked not used: Salgado (Rovers), Neville, Gibson (Man Utd)