Horan penalty gives USA comeback win over Japan
Japan had taken the lead after just 30 seconds but Jaedyn Shaw levelled in the 21st minute before Horan's spot kick in the 77th minute.
The match, at Atlanta's Mercedes Benz Stadium drew a crowd of 50,644, the largest crowd ever for a USA women's team friendly and the biggest crowd for any of the team's games in home soil since the 1999 World Cup final.
USA interim head coach Twila Kilgore left Paris Saint-Germain midfielder Korbin Albert out of the starting line-up after a row over social media posts from the player.
The 20-year-old Albert apologised after sharing content, including a religious video about transgender and LGBTQ issues, which was heavily criticised by former player Megan Rapinoe.
The retired former captain of the team, known for her activism, suggested that the content was contributing to 'hate' against the LGBTQ community.
Albert came on as part of a triple change in the 78th minute with the Americans already in the lead.
The huge crowd were quickly silenced when Japan scored on their first attack. Momoko Tanikawa feding Kiko Seike down the right and her low shot flew in off the inside of the post.
Striker Mallory Swanson, returning to the side after a year out with injury which cost her a place in the World Cup, went close with a left-foot shot which was cleared off the line by Japan defender Miyabi Moriya.
But the Americans, who had been on top, got on level terms when Sam Coffey won the ball in midfield, burst forward and then slipped a pass inside to Shaw who fired home with a low drive into the corner.
The goal was Shaw's fifth in her last five games for the national team.
Swanson went close again when Horan surged from midfield and threaded a pass through to the striker but Japan keeper Ayaka Yamashita was off her line quickly to smother the ball.
After the break, Trinity Rodman forced Yamashita into action again with a fierce drive that the keeper did well to parried out.
The Americans pushed hard for a winner with Swanson wasting a good opportunity, screwing a shot wide after good work from Sophia Smith to set her up.
It was Smith who won the penalty, dribbling into the box before she was brought down by Hina Sugita and Horan buried the spot kick into the bottom corner.
The USA will face the winner of Saturday's other game between Canada and Brazil in Tuesday's final in Columbus.