The Red Devils' boss believes the Dutchman's goals will alleviate fears of losing the title on goal difference again, and also backed Chicharito and Wayne Rooney to reach 20 goals
The Red Devils are currently top of the Premier League – as well as their Champions League group, but question marks have been raised about the quality of their backline.
However, United boss Ferguson believes the firepower he has up front will more than compensate, especially since Van Persie’s summer arrival from Arsenal.
"Last year we lost on goal difference and I don't expect us to lose on goal difference again - Robin may make that difference,” Ferguson told reporters.
"Robin's experienced. He had eight years at Arsenal which helps and he's come to us at the right time, there's no doubt.”
Dutchman van Persie has already scored 11 goals since his £24m move, drawing praise from his Scottish manager.
But Ferguson also found time to praise his other marksmen Chicharito and Wayne Rooney, suggesting the pair will both reach the 20-goal mark for the season.
Ferguson continued: "He [Van Persie] has got us 11 goals so far and Chicharito is on six and getting back to what he was a couple of years ago - a summer's rest has helped enormously.
"He's looking fresh and aggressive with his running, always a handful, and Wazza will get to 20 goals plus, I'm sure of that. It's a healthy combination we've got up there.
"Wayne had goals last year and the way Chicharito has started this season I'm certain he'll get to 20 plus."