''You have to know with Kristine,'' Wambach said. ''Sometimes in the course of a game she can get pretty much inside herself. When she gets inside herself, I know something good is about to happen.''
The victory boosted the United States to four points atop Group B — the same as North Korea — with a final group game Tuesday in Shanghai against Nigeria. North Korea defeated Nigeria 2-0 on Friday and faces Sweden on Tuesday in the northern city of Tianjin.
A draw will be enough to get the United States to the quarterfinals, although a victory might guarantee first place and a quarterfinal against Japan or England. If the U.S. finishes second it will have a tougher time against defending champion Germany.
''We knew that this was potentially an elimination match with Sweden,'' said American coach Greg Ryan, whose team is undefeated in 48 games since he took over 2 1/2 years ago. ''Big players win championships, and you saw what happened here tonight.''
Group B is by far the most difficult of the 16-team tournament, and Ryan described the first two games and nearly ''semifinals and finals.''
The other side of the bracket is much weaker, with China, Norway and Brazil among the favorites to reach the final eight.
The United States was pressed hard early in game in southwestern China, but the Americans took control after Wambach's penalty.
Defender Kate Markgraf started the first scoring play, sending in a long, soaring ball that was badly misjudged by Lindahl, who allowed it to bounce over her head. Racing to put in the loose ball, Chalupny was taken down in the area by Swedish defender Stina Segerstrom.
Whenever the United States couldn't find an open player, it launched long shots at Lindahl.
''I think every time you play in a high pressure situation you want to test the goalkeeper,'' Markgraf said. ''We just kept hitting balls at her. She kind of got rattled and we kind of knew it.''
The penalty wasn't clear-cut. Ryan said it looked like a good call, and Sweden's Dennerby said: ''I think it was a tough one, but that's the Swedish way to see it.''
American midfield Chalupny leaned toward a penalty, but acknowledged it was a close call, which shifted the momentum to the United States.
''The goal was right there and there was definitely some contact,'' she said. ''We were fortunate to get a goal, though.''
In the other Group B game, North Korea defeated Nigeria on first-half goals by Kim Kyong-hwa and Ri Kim-suk.
In Group A in Shanghai, Germany and England played a 0-0 draw. In the other Group A game, Japan defeated Argentina 1-0 on an injury-time goal by Yuki Nagasato.