The 37-year-old recently signed a one-year contract extension with United and O’Shea believes Giggs could carry on four at least another three years.
“Without a doubt,” said the Republic of Ireland star.
“His physical shape hasn’t changed since I’ve known him and he looks after himself so well.
“Depending on injuries he could easily carry on, although I am sure he just wants to take it one season at a time.
“He is just enjoying it so much at the minute so I can’t see why he can’t but I’ll let him decide on that.”
“You see how the manager has built squads and Giggsy has been a vital part of every single one of them,” he added.
“It’s just incredible. Maldini springs to mind with AC Milan but I think Giggsy has even gone past him.
“The speed and the balance he still shows to go past whether it be an old, experienced defender or a new, up-and-coming young strong defender is incredible.
“Every cliche in the book has been used about the man already and I am sure they will be said many times again.
“He is an absolute legend.”