Shanghai (AP): Defending champion United States edged Japan 1-0 to revive its chances of a third Olympic gold medal in women's football on Saturday, and World Cup champion Germany beat Nigeria 1-0 to move closer to a title it has never won.

Beaten 2-0 by 2000 Olympic champion Norway in their opening game Wednesday, the Americans were last in Group G and could afford no slip-ups against the Japanese in Qinhuangdao.

After goalkeeper Hope Solo had tipped a dipping shot from Homare Sawa over the crossbar, the Americans went ahead in the 27th minute when Carli Lloyd met a left-wing cross with a powerful shot into the roof of the net from just outside the box.

Japan goalkeeper Miho Fukumoto defied the U.S. team, the 1996 and 2004 Olympic champions, with a series of saves before Amy Rodriguez shot across the face of goal in the 81st minute. The U.S. now has three points from two games and Japan has one after a 2-2 draw with New Zealand.

``I am very happy about our performance today against, I would say, a technical and good Japan,'' U.S. coach Pia Sundhage said. ``I think the more minutes we get together in the Olympics ... the better it is, so we will improve our game from one game to another.''

In Shenyang, Germany defender Kerstin Stegemann turned home a cross from Anja Mittag in the 64th minute to score.

Cynthia Uwak had wasted a great chance to shock the Germans just before halftime when she dribbled past two defenders but lost control before she could shoot, allowing goalkeeper Nadine Angerer to race off the line and save at her feet. Angerer also pushed away a shot from Perpetua Nkwocha.

``We knew it was going to be a tough game,'' Germany coach Silvia Neid said. ``We had to fight our way into the game and it took us a little time to adjust to our opponent.''

After a 0-0 draw with World Cup runner-up Brazil, the Germans now have four points with no goals conceded and Nigeria is virtually eliminated with no points from two games.

Nilla Fischer's 57th-minute goal gave Sweden a 1-0 victory over Argentina in Tianjin to keep her team's hopes alive and all but knock out the South Americans. The Swedes, which had lost 2-1 to China on Wednesday, now have three points.

In later games, Norway played New Zealand in Group G, Brazil met North Korea in Group F and host China took on Canada in Group E.