Ferguson endured three difficult seasons with the Red Devils after taking over in 1986 but the club kept faith in him and have been rewarded spectacularly in the years since.
He finally bows out for good this weekend having won 13 Premier League titles, two Champions League trophies, five FA Cups and four League Cups for United, along with numerous other pieces of silverware.
Clarke is one of many in the game happy to laud Ferguson's achievements - but knows the patience United showed in him is unlikely to be seen again.
He said: "Would he get three years now like he did at United? No. I don't think so in this day and age. It just shows you, eh? Patience is a virtue. Nearly 27 years is a great shift. Listen, he did the hard work in Scotland.
"He started with St Mirren, my club, with a great tradition to build on. So by the time I got there Sir Alex had left but the players he brought into that club carried the club to European competitions for a number of years after that so he gave a good basis there.
"St Mirren did sack him. They were probably forced to sack him - I would imagine Sir Alex in those days was a bit fiery and ready to fight the chairman. I can't remember if the St Mirren chairman said he wasn't manager material, I was a young lad in those days.
"To be a manager or a head coach you have to be resilient; you have to know there will be bad times to go with the good times. The good ones have more good times than bad times."
Clarke added: "He went to Aberdeen and broke the Old Firm monopoly. He came down to England for another challenge and struggled for three years but he got the time to build because in those days you got the time to build.
"Over the years he's built a dynasty, one of the biggest clubs in the world and they just went from strength to strength, every year they were always challenging for honours so he did a fantastic job."
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