A goal wiped out by an official's call helped deal the U.S. women's team its first loss, a setback in its quest for the first American hockey medal in 12 years.
The Americans apparently tied the game, 1-1, with Britain when Barb Marois made a penalty corner goal with about seven minutes left to play. But the goal was nullified when an official ruled that the ball never came to a complete stop before the shot was taken, and the British held on for a 1-0 victory.
In other women's games, Australia beat Germany, 1-0; Argentina beat Spain, 1-0; and South Korea beat the Netherlands, 3-1.
In men's games, a late goal by inside right Jay Stacy earned Australia a 3-2 victory over South Korea. They were the only winners in the second series of group B matches.
Britain and the Netherlands played to a 2-2 draw, as did South Africa and Malaysia.