Abby Wambach scored the only goal of the half as the United States lead New Zealand 1-0 in their Olympic quarter-final clash.
It was the US who started the stronger, with Tobin Heath and Alex Morgan both testing Jenny Bindon within the opening two minutes of play.
New Zealand also threatened, and came close via Katie Hoyle after nine minutes, but she struck a long-range effort wide of the post.
The best chance of the opening period fell to Morgan moments later, but she just dragged her shot wide after rounding Bindon in the penalty area.
The US continued to dominate as the half advanced, but Wambach somehow slotted wide from close range as the scores remained level.
The goal eventually came for the US after 27 minutes when Wambach tapped home her fourth goal of the tournament to send her side ahead.
New Zealand continued to struggle in the latter stages of the half, with the US entering the break ahead.
