Louis van Gaal brought in the Colombian striker, one of football's biggest current names, on a season-long loan to Old Trafford from Ligue 1 side Monaco.
The Express quotes Ferguson as saying: "It's the rebuilding of the team and they brought in some good quality. It was really important because you need quality at Manchester United, you need the best players.
"What has pleased me about Louis is he's given seven young kids their debuts this year which falls into line with the history of our club, there's no question about that.
"The big one is Falcao who we're all waiting to see. Obviously, he has fantastic goalscoring ability. He had his injury so getting him on loan is the right thing to do."