Teen star Alyssa Thompson was watching from her aunt's house when the United States beat the Netherlands in the 2019 Women's World Cup final. Now she is helping the Americans prepare for a rematch.

The 18-year-old graduated from high school months ago and never expected to play in the World Cup so soon, with Thursday's group-stage showdown against the Netherlands in Wellington conjuring memories of her days as a national team fan.

"I just remember how intense it was and how back and forth it was, and it was a tough game and I was really nervous for the team," she told reporters on Monday.

"In that moment, I wasn't really thinking about, 'Oh, the next one, I'm going to be at,' because it felt like so far away. But being here now is crazy to me, because I didn't think about it in the moment."

She became the second-youngest ever to take the pitch for the United States in a Women's World Cup when she was subbed in during the 75th minute of their 3-0 victory over Vietnam on Saturday.

The forward was scarcely able to contain her joy at the match as she completed her stunning transformation from a youth soccer competitor to a World Cup contender in a matter of months.

"I was pretty nervous just to play my first World Cup game. But once I was on the sideline, I was kind of overcome with happiness and excitement, just because I was going into my first World Cup, and I wasn't feeling any other emotion," she said.

The ninth-ranked Netherlands, who beat Portugal 1-0 in their Sunday opener, are widely expected to be the Americans' toughest Group E opponent.

Thompson's teammate, defender Naomi Girma, said they are relying on the steady hand of their veteran corps, including fourth-timers Megan Rapinoe and Alex Morgan, to help them mentally prepare.

"They've just been telling us to enjoy the moment and soak it in, and I think in that first game that was really big - just staying calm and just knowing that it's a normal game and trusting ourselves to go out and get the job done," said Girma.

The United States play the Netherlands in Wellington on Thursday, before closing out their group against Portugal next week.