Hwang Yong-bong’s team conceded in the final seconds to lose 1-0 to Japan, having wasted several chances to take the lead.
But they more than made amends at the Jiangning Sports Centre with a classy display.
Ri Un-sim scored twice, while Ri Kyong-hyang and U Sol-gyong were also on target as Korea Republic were torn apart by the pace and strength of their opponents’ attack.
Victory over their rivals also put DPR Korea right back in the hunt for a top-three finish in the six-team round-robin tournament which would earn them a place at next year’s FIFA U-17 Women’s World Cup.
Both sides began cautiously, with neither wanting to give anything away in the early stages.
But DPR Korea broke the deadlock in the 21st minute when the ball broke to Ri Kyong-hyang on the left edge of the area and she curled an effort into the near top corner.
Rim then had to be alert to tip a free-kick from deep over the bar when it threatened to bounce over her head and into the net.
But DPR Korea doubled their lead four minutes before the break when Ri Un-sim stabbed home a low cross from the right from close range.
Korea Republic made a double substitution at the break in a bid to find a way back into the match.
But they were still getting no change out of a very well-organised DPR Korea backline.
Kim almost fashioned a chance out of nothing when she collected a long ball and, with no support, held off a defender and fashioned a shooting chance before firing a shot over the top.
But DPR Korea put the result beyond doubt in the 65th minute when U knocked the ball home after Ri Hyang-sim’s shot was well saved by the legs of the South Korean keeper.
And three became four seven minutes later as Ri Un-sim nicked the ball past the last defender and slid a low shot into the corner to complete a convincing victory.