Speaking after the 4-2 aggregate victory over Chelsea, a jubilant Cassell told City's website: "I can’t tell you how pleased I am - it must be obvious to everybody.
"We have had a personal campaign if you like over the years to try and win the Youth Cup because I feel what we’ve done within the Academy system, at some stage, we deserved to get a national trophy for it.
"Everybody knows that it’s about producing players, we have done that and I hope we continue to do that, but it’s so emotional and rewarding to win the Youth Cup.
"It’s a national trophy and we are the champions and I’m so proud of all the boys and for the staff.
"I think that the real people that need the credit, of course, are the players because they have to go out and do it.
"Obviously there’s a lot of attention on Alex and myself but at the end of the day everybody within the Club on the Academy side has done their job. It should be just reward for them as well as the players."