South Korea are on track to qualify for the Olympic quarter-finals despite wasting several first-half chances against Gabon at Wembley.
The Asian nation need just a point to guarantee their progress to the last eight, but a win could secure them top spot in Group B.
Their inability to convert a handful of opportunities will come as a frustration to manager Myung Bo Hong.
Arsenal striker Park Chuyoung saw his early effort stopped by the goalkeeper while Jacheol Koo was also denied by Gabon stopper Didier Ovono.
Koo missed perhaps the best of the first-half chances as he struck wide from a good position on 27 minutes.
Gabon had chances of their own, but Axel Maye twice sent efforts off target as the opening period ended goalless.
