In search of a victory, New Zealand coach Darren Bazeley made five changes from the side that lost 4-0 to the US during the week.
Midfielder Matthew Ridenton was one of the surprise omissions, while he also brought in goalkeeper Nikola Tzanev in place of Oilver Sail.
Alex Rufer, who is generally more at home in the midfield and wasn't picked to play the US, was again commissioned up front, which is the same role he performed in New Zealand's opening match with Ukraine.
It was Wellington's Noah Billingsley who got New Zealand's first goal of the tournament when he scored from close range in the 40th minute as the 17-year-old connected with a nice cross from Deklan Wynne.
The goal cancelled out the opener from Myanmar, which had come via an impressive finish from Aung Thu.
With the scores locked at 1-1 at halftime, the game was set up nicely for one team to stamp their mark on it.
Myanmar, making their first appearance at an Under-20 World Cup, were rated as large outsiders coming in to the contest but they were dangerous on the counterattack.
Billingsley, the youngest member of the New Zealand squad, had a foot in their second goal as part of a quick move in the box, which saw Monty Patterson score shortly after the break.
Playing from in front suited the Junior All Whites who displayed a greater level of confidence with the scoreboard in their favour.
If 2-1 looked good, then 3-1 must have felt great as super-sub Joel Stevens scored within a minute of coming on the field.
Sam Brotherton added to the rout when he delivered a bullet header from a corner at the same end where Rory Fallon scored that famous goal for New Zealand against Bahrain in 2009.
Clayton Lewis also got on the board in the final minutes.
New Zealand 5 (Noah Billingsley 40, Monty Patterson 47, Joel Stevens 78, Sam Brotherton 81, Clayton Lewis 89)
Myanmar 1 (Aung Thu 28)
Halftime: 1-1