United remain a point adrift of Chelsea, having played a game more than the Stamford Bridge outfit, and with just four matches to do something about it.
To make matters worse, Rio Ferdinand picked up a groin injury, Ryan Giggs was forced off with a hamstring strain and John O'Shea also left the field early as he started for the first time since November.
It made for a pretty bleak afternoon and Ferguson was not trying to hide his disappointment.
"It was a bad result," he said. "We had to win every game going into today and we didn't do it. That is the disappointment.
"It has slipped away from us today.
"It is going to be very difficult to win this league. We have a lifeline if Chelsea blow it.
"But to my eyes they have an easy game against Bolton on Tuesday. We would expect them to win that and it will put them four points clear."
Ferdinand had already been in the wars, dislocating his finger in a collision with Martin Olsson.
But it was the groin injury he sustained near the end that will worry Ferguson more, and probably Fabio Capello as well as the World Cup starts to loom into view.
"Rio dislocated his finger but ended up with a groin injury," said Ferguson.
"We effectively had 10 men on the pitch at the end, which is not good when you are chasing a victory."
Although United dominated possession, with Wayne Rooney out with an ankle injury, they created few clear-cut chances.
Antonio Valencia had the best one just before the break when he found himself clear inside the penalty area.
But Paul Robinson produced a fine save to repel the Ecuador star and United came no nearer even though they spent long periods camped in the Blackburn half.
"We had so many opportunities in the last third of the field and our decision-making has let us down," said Ferguson.
"The ball just jumped up on Valencia a little bit. He should have scored.
"That would have put us in front just before half-time and Blackburn would not have come back at us."
After spending Thursday with Ferguson at Aintree Races, Blackburn manager Sam Allardyce dispelled the theory he might do his old friend a favour.
His side are now firmly entrenched in mid-table and are proving very difficult for the big boys to overcome, particularly at Ewood Park.
"Nobody gets it easy here," said Allardyce. "We have had Chelsea here twice, we have had Liverpool here, now we have had Manchester United here and none of them have managed to beat us. It shows how much we have grown."
Indeed, Rovers have lost just three home matches in 28 since Allardyce took charge last season - a run Chelsea no doubt hope continues given Arsenal, now their closest rivals, have still to travel north.
For United, it marks the end of a miserable fortnight, which has seen their hopes of glory on the European front ended and in the league almost snuffed out too - not that Allardyce is throwing in the towel on their behalf.
"We have done a good bit of damage to their title hopes," he said.
"But when Chelsea drew here everyone said they were finished. Look what they have done.
"United might win all four games and Chelsea might slip up somewhere along the line."