Scot will oversee his final-ever home game against Swansea City on Sunday.
Former England manager Fabio Capello says that Manchester United boss Sir Alex Ferguson decided to retire from all forms of football due to the stress of his job at Old Trafford, reports the Daily Mail.
Ferguson, 71, shocked the world of football by announcing his decision to quit as United head coach on Wednesday after 26-and-a-half years in the north west.
And the former Three Lions trainer says that he spoke to the Scot about his surprise decision, with Ferguson explaining to him the exact reasons as to just why he was retiring.
“A few months ago he told me that he was going to stay on. The news of his retirement really surprised me,” said Capello.
“I called him and he told me about the stress. He also told me that now he’ll go and travel a bit, have fun and see the world with his wife.
“He was the greatest coach of all time, especially because of all the difficulties he overcame at the start of his career with United.
“I normally think, after four or five years at the most, a coach should move, so to think that he stayed on the same bench for 26 years is incredible. That takes psychological, technical and humane capacity.”
Ferguson has been in charge of the Red Devils since Nov 1986, during which time he has overseen a quite incredible 1,498 matches, winning 894 of those contests and losing just 267, giving the veteran an impressive overall win percentage of 59.
And, Ferguson has also won 13 Premier League titles and two Uefa Champions League crowns during his illustrious career at United.