With Germany favoured to progress to the last 16 from Group H after their 6-0 thrashing of Morocco on Monday night in Adelaide, Tuesday's match at Allianz Stadium was massive for both sides.
In the clash between the last two of the 32 nations to play their tournament opener, the South Americans scored twice in nine first-half minutes to secure the points.
South Korea had the first three shots of the game, but Colombia looked the more consistently dangerous side after the first 20 minutes.
A well-taken 30th-minute penalty from 33-year-old Catalina Usme, Colombia's all-time leading goalscorer gave them the lead after a shot struck the arm of Shim Seoyeon.
Linda Caicedo, the 18-year-old, who survived a cancer scare earlier in her teens, doubled the lead.
The highly rated youngster, who plays for Spanish giants Real Madrid, surged down the left and cut inside before firing a curling shot from just outside the area which squirmed through the hands of goalkeeper Yoon Younggeui.
Caicedo constantly threatened the world No.17 nation and was named player of the match.
South Korea's best chance came in the tenth of almost 12 minutes first-half added time.
Lee Geummin had a free header from seven metres out, but goalkeeper Catalina Perez pulled off a fine save.
Early on, Perez comfortably saved on target shots from Cho Yuri and former Chelsea star, Ji Soyun, the latter from a short free-kick which the star midfielder lifted over the wall.
As the half progressed Colombia started to look more dangerous in the final third and they took control after hitting the front.
Colombia had 17 attempts to five, though only two more shots on target, with the Asian side struggling in the second half to create opportunities and rarely threatened on goal.
South Korean Casey Phair became the youngest player in Women's World Cup finals history when the 16-year-old came off the bench in the 78th minute.
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