World champions Germany took a big step towards a place in the quarter-finals of the women's Olympic football tournament with a 1-0 victory over Nigeria in Shenyang on Saturday.
Kerstin Stegemann (right) scored an important goal for Germany
Defender Kerstin Stegemann struck in the 65th minute for the Group F win which followed a goalless draw against Brazil.
Olympic champions United States bounced back from defeat to Norway by overcoming Japan 1-0 in a Group G match in Qinhuangdao, with midfielder Carli Lloyd volleying the 27th-minute winner.
In Tianjin, Sweden recovered from a 2-1 opening defeat to China by defeating Argentina 1-0 in a Group E game.
Brazil went ahead in the 14th minute when North Korea defender Om Jon Ran over-hit a backpass, goalkeeper Jon Myong Hui tried to stop it going out of play but instead kicked it straight to Daniela who scored into an empty net.
Nine minutes later, Marta beat her hesitant marker to the ball and scored on the turn.
Ri Kum Suk scored North Korea's consolation in injury-time.
Brazil, who have four points from two games, top Group F on goals scored from Germany.