The 24-year-old scored the only goal of the game in a 1-0 triumph for Gregg Berhalter's side, who secured a second-placed finish in Group B to advance to the last 16.
Pulisic darted into the box to tap home in the 38th minute, but he suffered a heavy collision with Iran goalkeeper Alireza Beiranvand in the process and was left grimacing on the floor.
The attacker was helped to his feet by the medical team and was able to see out the rest of the first half, but he had to be replaced at the half-time break by Leeds United's Brenden Aaronson.
Pulisic was taken to hospital for abdominal scans st the Stars and Stripes held on for a 1-0 victory, and he posted a positive update from his medical bed following his nation's qualification to the knockout rounds.
The USA will take on Group A winners Netherlands in their last 16 clash at the weekend, and Pulisic affirmed that he would be fit for the contest, posting on Snapchat: "So f****** proud of my guys I'll be ready for Saturday don't worry."
Following Tuesday's win, the USA confirmed on social media that Pulisic had been diagnosed with a pelvic contusion, and he would continue to be closely monitored ahead of the weekend.
Berhalter was asked for an update on Pulisic's fitness at the full-time whistle, and while the USA boss could not relay any fresh information, he lauded the efforts of his number 10 at the Al-Thumama Stadium.
"No update (on his fitness), but it is a wonderful thing when one of your best players is one of the hardest working," Berhalter told the press. "And he is certainly that. I can't say enough positive things about Christian."
Pulisic's strike against Iran represented his first goal of the 2022 World Cup, while he also claimed an assist for Timothy Weah's opener in the USA's 1-1 draw with Wales on November 21.
The former Borussia Dortmund starlet has now amassed 22 goals and 13 assists in his 55 caps for the United States, and he sits seventh in his country's all-time scoring charts.
Pulisic needs just three more goals to overtake sixth-placed Joe-Max Moore (24), but he remains behind Brian McBride (30), Eric Wynalda (34), Jozy Altidore (42), Landon Donovan and Clint Dempsey (both 57).
Despite his success at international level, Pulisic's Chelsea future is being called into question, with the attacker only starting three Premier League games and one Champions League match for the Blues in the 2022-23 season.
The likes of Manchester United, Arsenal and Newcastle United are said to have been impressed with his performances at the World Cup, and he is only under contract at Stamford Bridge until 2024.
However, a recent report claimed that Pulisic was keen to stay and fight for his place in Graham Potter's side.