Grealish received a surprise call-up to the squad for the Barclays Premier League clash against Chelsea in March at the age of just 16.
He was handed the No.41 jersey and was an unused substitute as the claret and blues lost 4-2 at Villa Park.
The Birmingham-born attacker had already demonstrated his exciting potential for the youth, reserves and NextGen Series sides.
He scored the first of his five goals for the U18s in a 3-2 victory over Watford in November.
Grealish then produced a sensational display against Norwich in March, winning and scoring a penalty before securing the points with a fine individual goal.
His sparkling form continued and he was rewarded with further goals against Crystal Palace and Portsmouth.
Grealish made a string of appearances from the bench for the reserves but also impressed in a starting role during a 1-0 win over Chelsea.
In the NextGen Series, Grealish came off the bench to feature in all but one of Villa's clashes.
The Republic of Ireland youth international was particularly impressive in the 4-1 victory over Norwegian side Rosenborg, setting up goals for Graham Burke and Michael Drennan.
Grealish finished the season by helping Villa reach the final of the Hong Kong International Soccer Sevens.