Thursday's 0-0 draw probably favours the Asian team, who worked hard at the Education City Stadium against their more fancied opponents.
South Korea, with forward Son Heung-min wearing a mask to protect a broken left eye socket, always looked capable of scoring against the more experienced Uruguayans.
The South Koreans were quicker, pressing from the opening whistle.
Some South Korean fans wore Batman-like masks in solidarity with Son.
However, in a match with few clear scoring chances, Uruguay had the clearest chances: Diego Godin hit the post with a header from a corner in the 43rd minute and Federico Valverde hit it in the 89th.
Uruguay will next face Portugal in Group H while South Korea plays Ghana.
South Korea attacked from the start and Son excited the crowd every time he touched the ball. He managed only one threatening attack in the first half, however, and did less in the second.
South Korea always looked quicker than Uruguay, but not necessarily the more dangerous. The team's best chance came in the 34th minute when Hwang Ui-jo blazed a close-range attempt over the crossbar.
As the half wore on, Uruguay began to take more possession but always seemed more cautious, taking less initiative despite having the more experienced players.
Son went down in a heap early in the second half with Martin Caceres getting the first yellow card of the match.
Uruguay coach Diego Alonso sent in Edinson Cavani for Luis Suarez in 64th minute as the pace of the match slowed until Real Madrid's Valverde hit the post from outside the box in the final minutes.
11°C