Ferguson turned 69-years-old last month, but Giggs believes his veteran boss could stay at Old Trafford for well into his seventies.
In an interview with Sky TV magazine, Giggs said: “I really do not see him (Ferguson) finishing any time soon, he will go on, at least another five years.
“His desire gets stronger. After a Champions League game we can get back at 3.30am and then a few hours later he will be the first in at the training ground.
“Earlier in the season we had a virus at the club. He got it himself and was dying during the week, really sick, but come the day of the game, he was there in the dug-out. He just loves the challenge.”
