Allardyce has made an instant impact at Ewood Park, having suffered just one defeat in his first seven games in charge.
But the club are still just one point from the foot of the table and the Rovers boss has much more work to do if he is to steer them to safety.
Ferguson, though, believes Allardyce is the right man for the job and has heaped praise on the former Bolton boss for his achievements in such a short space of time.
Up to the task"I am sure Sam will keep them up," the Scot said. "It is not easy down there. After the New Year, very seldom does a team gather the points they think.
"There are not many examples, West Ham a couple of years ago springs to mind, when a team goes on a long run. But that was unusual.
"Normally it is a point, or a point and a half per game at the most."
The United boss believes that with so many clubs involved in the relegation battle this term a minimum of 43 points may be required to avoid the drop.
"It is tighter than ever," he said. "You could say 10 teams are involved. Every time they play you can imagine the pressure on everyone involved.
"Sam is well aware of that but he has the experience to handle it."
StunnedThe United boss admitted to being stunned at the sacking of Luiz Felipe Scolari after just six months at Chelsea, saying the pressure on management is now greater than ever.
Having won 10 titles and two Champions League crowns in his 22-year stint at Old Trafford, Fergie is a shining example of the success a club can enjoy if they show a little faith.
Despite his achievements, though, the Reds boss believes some owners - at the moment - don't have the patience to give a manager time to settle.
"In the world we live in, success is demanded quicker than ever I'm afraid," said Ferguson.
"There is no such thing as trial and error any more. Now it is trial and success for everyone."