In a match that never reached any great heights, Gaston Pereiro showed why he has been widely touted as a future superstar.
Pereiro, Uruguay's second top scorer during qualification, somehow slipped behind Serbia's last line of defence to tap home a lofted ball into the box in the 56th minute.
The Serbs thought he was offside when he made his run, and replays showed it was an awfully close call.
While the result means Uruguay is atop the group D standings with Mali on three points, Serbia now faces an almost must win game against Mali on Wednesday.
The Europeans had plenty of ball and almost grabbed an equaliser through Ivan Saponjic in the 76th minute, but his driving shot was saved by goalkeeper Gaston Guruceaga.
Just a few moments later, Sergej Milinkovic barely blasted wide of the goal, but there would be one more golden opportunity for the Serbs to salvage a point.
Saponjic made a run on goal in the 83rd minute to create a one on one chance with the goalkeeper, but again Guruceaga was up to the challenge.
The Uruguayans would have felt hard done by had he scored, as Saponjic appeared to be well offside when he made his run.
Despite the loss, Serbia can take plenty from a match it probably deserved to draw. Uruguay had the best first half chance when Pereiro got on the end of a Facundo Castro cross, but his powerful header was brilliantly saved by goalkeeper Predrag Rajkovic.
After a slow start, Serbia grew as the match went on and created more chances than Uruguay, the 2013 runner up. Making its first appearance in a Fifa Under 20 World Cup, Serbia fired 15 shots on goal, seven of them on target.
Andrija Zivkovic, who has already played for his country's senior team and is being watched by clubs all across Europe, was heavily involved, as were Saponjic and Mijat Gacinovic.
Uruguay v Serbia
The scores
Uruguay 1
Gaston Pereiro, 56
Serbia 0
Halftime: 0-0
In summary
Uruguay overcame a stubborn Serbian side to pick up the all important three points. It was not pretty, but points are not awarded for style.
Star player
Gaston Guruceaga had an absolute blinder in goal for the South Americans, making a bunch of brilliant second half saves to rebuff Serbia's late push for a draw.