United States women's national team goalkeeper Alyssa Naeher was in disbelief after a razor-thin penalty decision against Sweden ended her side's run at the Women's World Cup round of 16.

"Someone said there was a picture of it and it was off by a millimeter," Naeher said. "It's tough to have your World Cup end by a millimeter."

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She added: "I thought I had it. It must've slipped in."

After a scoreless 120 minutes, Sweden won a penalty shootout 5-4 to advance. On the final game-deciding kick from Lina Hurtig, Naeher made an initial block in which the ball popped up and backward toward the goalline, and then she knocked it clear. Naeher confidently told the referee she made the save, but an automated decision from ball sensors showed the ball had barely crossed the line fully.

"That was a crazy situation," Hurtig said. "First I thought it went in and then it took some time before the referee ... I think they said to her that the ball went in and but it was long seconds we were made to wait."

Naeher saved one kick from Rebecka Blomqvist and even scored a penalty, kicking sixth in the rotation, but USWNT stars Megan Rapinoe, Kelley O'Hara and Sophia Smith all missed their penalties.

"I've got all the confidence in the world in all 23 of us to step up and take PKs," Naeher said. "Unfortunately we weren't able to put them away tonight, but it doesn't take anything from Pinoe, Kelley and Soph. They are fantastic players and I feel for them, too. It's tough -- they've trained for it, they've prepared it. Unfortunately those things happen and my heart hurts for them."

The USWNT's exit in the round of 16 is its earliest at any major tournament and marks the first time the Americans failed to reach the semifinals of a World Cup.