Director of football Gradi has watched the Haslington lad progress through the academy ranks, and believes it proves the 'Crewe way' is the ideal model for aspiring young footballers.
He told the Crewe Chronicle: "In all the time I've been at the club, it is the first time we have sold one of our players to Manchester United.
"We have had a few from them in the past, with David Platt being the obvious one, but this is the first one they have signed from us. This is the best way to do things. We have always said it and Nick has followed that route.
"He had opportunities to go to bigger clubs when he was coming through the academy but he stayed with us. He knew he would get a chance to play at an early age and when they go into our team early, they are usually the ones who go to the bigger clubs.
"Nick went into the team early and proved he was good enough very early as well. We lost one (Dan Smith) to a bigger club (Liverpool) a few months ago for a few hundred thousand pounds and we were trying to inform him that there was a better way to do it.
"Nick is a match winner, he doesn't have to rely on players to set him up in the six-yard box. He can score great goals and he has signed with a terrific club where he will improve."