USA have made it nine points from three games with a 1-0 victory over North Korea in Group G.
It was the United States who started the stronger and they could have been two ahead inside eight minutes but for Alex Morgan missing two gilt-edged chances.
The US continued to dominate as the half advanced, and Morgan struck the post with 15 minutes on the clock.
The chances continued to fall for the United States and Megan Rapinoe missed the target after 22 minutes. The goal did eventually come, however, when Abby Wambach converted after 25 minutes.
Korea continued to struggle in the latter stages of the half, with Rachel Buehler coming close to USA's second just moments before the break.
It was Korea who created the first chance of the second period, but Nam Hui Kim could not convert from close range. USA remained a threat, however, and Tobin Heath missed the target with an effort moments later.
Gyong Ye Ri was next to come close for Korea after 65 minutes, but she dragged her shot past the post.
Chances remained few and far between in the latter stages, although Wambach might have added her side's second with an effort after 75 minutes.
Korea were reduced to 10 men late on when Gyong Mi Choe was dismissed for a second bookable offence, while Lauren Cheney twice came close to extending USA's lead.
However, it remained 1-0, and Korea must now await their fate following the conclusion of New Zealand versus Cameroon this evening.
