Powell's 16 goals in 2011/12 helped Crewe Alexandra win promotion to League One (via a play-off final in which the 18-year-old netted brilliantly) and he became the first person in Crewe's history to scoop all five major prizes at the club's end-of-year awards night.
Such a talent was never going to escape the attention of England's biggest clubs and, after watching him in action against Torquay in early May, Sir Alex was determined Powell would sign for Manchester United.
"We sent people to see him a few times after he started scoring a few goals," the United boss told ManUtd.com. "He actually first came on our radar a few years ago when he played against our youth team.
"But we watched him seriously from February. Mike Phelan went to see him a few times and so did our chief scout, Jim Lawlor. My brother Martin also went to see him against Torquay before I went for myself, with Mike, when Crewe played Aldershot."
Powell wasn't at his best that afternoon but Sir Alex saw enough in the teenager to convince him he had a future at Old Trafford.
"We were thinking things over," he recalls. "We'd seen a few other Premier League clubs there at the game - Everton, somebody from Arsenal, somebody from Chelsea (they were very keen on Nick) - so we thought it was best to set the wheels in motion.
"In these situations, I always think about the time we signed Lee Sharpe. We went to watch him and we were impressed. The dilemma was this: do we go home and think things over or do we make a decision