The in-form Liam Delap scored a superb hat-trick to continue his remarkable goal-scoring form, and round off a quite incredible performance from the City youngsters.
Delap has now scored a remarkable 13 league goals in his last six games, bringing his league tally for the season to 19.
The victory sees Maresca's side regain our five point advantage at the top of the Premier League 2 table, as we enter the final six games of the campaign.
After an even start it was City who had the first real opportunity of the match 10 minutes in.
Moments later Delap had another golden opportunity to open the scoring, as he beat the offside trap to get in behind the Saints defence.
This time he was denied by Southampton goalkeeper, Jack Bycroft as Delap's one-on-one effort from the edge of the box was well saved by the Saints' number one.
Despite two early misses, the City forward was in no mood to end his recent magnificent goal-scoring run as he finally found the opener on the half-hour mark.
It didn't take long for Maresca's side to get going in the second half, as we doubled our lead five minutes after the restart.
Maresca's side had been in rampant goal-scoring form of late, netting an incredible 16 goals in our previous four games, and that free-scoring form continued apace.
Delap added his second and City's third, 10 minutes into the second half, after he latched onto a Sam Edozie through ball and slotted past an out-stretched Bycroft.
A minute later we then had our fourth, as a loose ball fell to Bernabe on the edge of the box and the Spaniard smashed a fierce effort into the bottom corner to cap off a stunning start to the second half.
Caleb Watts did rescue some pride for the visitors as he pulled back a consolation, after a curling an impressive effort from 20-yards into the top corner.
Despite the three goal-advantage City did not hold off, as Delap completed his hat-trick with 10 minutes left after bundling in from six yards. for his 19th league goal of the season
Just two minutes later it was substitute, Nmecha's turn to find the net as he scored a quickfire brace inside five minutes from close range to finish off a goal scoring masterclass from Maresca's youngsters.
HOW WE LINED UP
Liam Delap led the line up-front.
WHAT IT MEANS
The victory means City remain at the top of the Premier League 2 table, five points ahead of second place, Blackburn Rovers.
Maresca's side return to action on Sunday 21 March, as we take on Chelsea away from home at 10:30am (UK).
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