Paul Ince says there will never be another manager who will enjoy the same level of success achieved by Sir Alex Ferguson.
Ince spent six years under Ferguson at Manchester United, after he signed from West Ham in 1989.
Ince admits he is in shock at the announcement that Ferguson would be stepping down at the end of the season.
"I was totally shocked. What he has done is unbelievable," he told Sky Sports News.
"You can't explain winning all those Premier League titles not to mention the Champions League, FA Cups - he has done the lot and you will never see anyone of his kind again.
"Two weeks ago he was talking about staying on for another two years so it has come as a massive shock."
Ince admits that Ferguson was a 'father figure' to him at Old Trafford.
"I was one of the fortunate ones; I spent six fantastic years at Manchester United. I remember the first day I joined - I failed my medical and thought my move was going to collapse. But the way he treated me was like a son and I will never forget that.
"He was demanding and his standards were so high - we had our ups and downs but I think he had his ups and downs with most players especially in that 92-93 season. But as far as total respect, the man was immense and he got the most out of me that was for sure.
"As a manager when I was at Blackburn things were not going well and I spent 15-20 minutes in his office. He said to me 'the only advice I can give you is don't let the players take the mickey out of you - don't give them anything, if you give them an inch they take a mile'."
On Ferguson's replacement, Ince added: "His replacement has to be someone with a massive character, someone who can deal with what it takes to be a Manchester United manager.
"It is going to be hard, Manchester United fans have just known one man. Whoever comes in is going to have to deal with the Man U legacy and the history that Fergie has left behind."
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