The United States women's soccer team remains on course to defend its Olympic title after reaching the semifinals on Friday, while rivals Brazil and Great Britain crashed out.
The U.S. beat New Zealand 2-0 to set a Monday clash with North American rival Canada, which defeated host Britain 2-0.
In the other semifinal, World Cup champion Japan will play first-time Olympic qualifier France.
Veteran striker Abby Wambach gave the U.S. a 27th-minute lead as she turned home a cross from fellow forward Alex Morgan at the far post, making up for the duo's earlier misses.
It was her fourth goal in four games so far in the tournament, and eighth in all Olympic appearances.
"Everything she does on and off the field, she leads this team. If you look at this game today, she scored a huge goal," coach Pia Sundhage said of the 32-year-old Wambach, whose 142 international goals from 186 games is second only behind former teammate Mia Hamm in the scoring stakes.
Morgan had three more second-half chances but the Americans could not make the game safe until the 87th minute when her replacement Sydney Leroux scored.
"We thought that we needed a little bit of a spark," Sundhage said. "This bench will win games for us. The fact that Syd Leroux comes in and changes the game a little bit is huge for us and for her."
Canada, which will host the next World Cup in 2015, ended GB's hopes of a medal in the team's first Olympic appearance as Jonelle Filigno and Christine Sinclair scored in the first half.
Britain had beaten Brazil to qualify top of its group, but could not find the net despite constant second-half pressure and a strong shout for a penalty kick.