The 71-year-old joined the Manchester club in 1986 but endured three years without silverware before they finally won the FA Cup, kickstarting a period of dominance that eventually brought with it almost 40 trophies, including 13 Premier League titles.
Clarke, however, is adamant that Sir Alex would not be afforded the same amount of time nowadays, keen to laud his fellow Scot's incredible legacy at the club.
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"Nearly 27 years is a great shift, he 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."
Clarke also spoke of Sir Alex's early career at St Mirren, a club for whom the Baggies manager played over a five-year spell, praising the foundations that his compatriot had left the side in his first managerial role.
"He did the hard work in Scotland. He started with St Mirren, my club, with a great tradition to build on," he recalled. "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."