His audacious goal in midweek against Middlesbrough left Giggs just five away from becoming only the ninth player to score 150 times for the Old Trafford outfit.
And although his present contract expires next summer, Ferguson can see no reason why Giggs should not get another.
"Ryan is an incredible human being. He could play for another year, no problem at all," said Ferguson.
"He might be 35 in November but he is exceptionally fit.
"The secret is to manage him the right way because he can still decide games for us. We just have to keep him fresh and make sure he has the motivation because I want him to continue.
"He is a fantastic person to have about the place. The experience he brings is invaluable.
"There are certain types of people you only get once in a lifetime. Ryan is just a complete one-off."
On Tuesday, Giggs floated around behind Cristiano Ronaldo and Danny Welbeck, creating havoc wherever he went.
At the same time, Nani was doing the job that was once his, forcing the Boro defenders onto the back foot with his dazzling wing play.
That task is no longer Giggs' to perform, with Ferguson certain the former Wales captain can be equally effective in his new central role.
"At 34, tramping up and down the touchline is beyond Ryan now," said Ferguson.
"You have to respect the job he has done for us going up and down that touchline over so many years.
"No-one in the Premier League comes anywhere near him in terms of his adaptability.
"But I look upon him as a central player, either in midfield or up front."