Former Manchester United striker and club legend Denis Law said he was really surprised to hear Alex Ferguson has decided to retire, adding that he thought Fergie would manage until he was 90.
He said: "I said a couple of weeks ago that when Sir Alex eventually retires at 90 he will probably go down as the greatest manager of all time. This morning I hear the news, and I was really surprised. I had no idea that he was going to do that."
Sir Alex Ferguson's brisk way with words has influenced the way we talk about football.
A timeline of the life of outgoing Manchester United manager Sir Alex Ferguson.
A special photo gallery of Sir Alex Ferguson's career at Manchester United as he steps down from his post as manager of the club.