USA, Korea Republic and Tanzania now have five points each from three matches.
Both the teams played with controlled aggression. USA, who had the ball possession in the first 15 minutes, created a couple of chances but without success.
Korea Republic, who took time to settle down, put pressure on the rival defence but their moves fizzled out as USA held their nerves.
Both teams preferred to play it safe in the second half, and fancied their chances on the counter. Korea had the best chance to surge ahead when Park Chanbin's cross from the left went abegging as Kim Taehwan was late to tap in.
With both teams trying to break the deadlock, they found the net once but referee Tejas Nagvenkar ruled off side.
Korea play their last match against India, while USA take on Malaysia.