Former Manchester United captain Bryan Robson said Sir Alex Ferguson's greatest achievement was his first league title in the 1992/1993 season - surpassing the club's treble in 1999.
Robson added that Sir Alex's success as a manager was down to his "determination" and "judgement on players."
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.