After opening the scoring just two minutes into the clash, the West Ham midfielder doubled his tally and put his side 4-0 up with a fine individual effort to further highlight his vast potential.
Following a John Stones header which went for a goal kick, Zaha appeared to engage his team-mate as he trotted back into position, causing the pair to exchange words before Morrison pushed his team-mate in the face.
Nathan Redmond came between the two and had to further restrain Zaha to stop him continuing the spat.
|12/1||Ravel Morrison is 12/1 with Coral to score the first goal in West Ham v Manchester City
Zaha, meanwhile, has so far not turned out for United since the Community Shield on August 10 and would been keen to join Newcastle on loan in January if he cannot force his way into David Moyes's plans.
Tuesday's match took place just hours before the senior side sealed qualification to World Cup 2014 in Brazil and was an opportunity for the Young Lions to push for a place in Roy Hodgson's selection next summer.
The comprehensive victory further strengthened the youth side's qualification chances for the 2015 European Championship, as they now sit top of Group 1, level on points with Wales but with two games in hand.