The Americans needed a win to qualify after drawing their first two games and that is exactly what they did thanks to a first-half goal by Christian Pulisic.
Greg Berhalter’s team finished second in Group B with five points and just one goal conceded a late Gareth Bale penalty in the first game.
Iran 0-1 USA
The United States have been a model of defensive solidity and energetic high-pressing throughout this tournament which is how they continued against Iran.
Timothy Weah spurned the first real chance of the game by shooting over, signalling the Americans’ intention to win.
Iran did sweep forward but Mehdi Taremi just hesitated at the sight of goal and gave the USA time to recover.
The USA pressure would eventually pay off as they took a deserved half-time lead when McKennie’s cross-field pass found Sergino Dest and he headed precisely back across goal for Pulisic to finish in the 38th minute.
The Chelsea winger collided heavily with goalkeeper Ireza Beiranvand and was replaced at half-time by Brenden Aaronson after struggling to finish the first half.
Iran improved in the second half, sensing a defeat meant elimination and a draw would prevent that but they ultimately failed to create clear-cut chances and the United States successfully held on to their lead.
The result means USA finished second in Group B with five points, behind England who won the group with seven points.
The United States are now through to the 2022 FIFA World Cup round of 16 where they will face the Netherlands.