FIFA defended the World Cup referee at the center of the Folarin Balogun controversy on July 6 after the official was branded "very suspect" by U.S. President Donald Trump.
In a statement, FIFA said Brazilian official Rapahel Claus had "demonstrated the highest standards of professionalism and integrity" throughout his career.
Claus had shown U.S. striker Balogun a controversial red card last week, prompting Trump to lobby FIFA to review the forward's one-match suspension.
FIFA subsequently reprieved Balogun, allowing him to play in Monday's last-16 clash against Belgium in Seattle, in a decision that has been widely criticised.
Trump had questioned Claus's refereeing credentials while speaking to reporters in the White House earlier on Monday.
"This referee, who is a little bit suspect if you check his past. I don't want to say that because I don't like to create controversy, but very suspect. He made a call that nobody could believe," Trump said.
The remarks had already been condemned by the Brazilian Football Confederation (CBF), who said there was nothing in Claus's background which "gives grounds for suspicion."
FIFA chief refereeing officer and chairman of the referees committee Pierluigi Collina, said Claus was a key member of the World Cup referees pool.
"Raphael Claus is refereeing at his second FIFA World Cup having been with us in Qatar in 2022," Collina said in a statement.
"He is an experienced and highly respected referee and we maintain full confidence in him as a trusted match official."
FIFA chief Gianni Infantino defended the decision to reprieve Balogun after Trump said he had appealed directly to the head of world football's governing body over the issue.
Under pressure to explain FIFA's decision to allow Balogun to play, Infantino insisted that his organization's disciplinary process was independent and he could not influence it.
That came after Trump confirmed he had contacted Infantino directly about the red card.
Trump told reporters at the White House he had called Infantino, with whom he has built a close relationship, "because I didn't think it was a foul".
"All I did was ask for a review, I didn't say you have to do this," Trump added.
Infantino said he had explained to Trump that "there was an ongoing legal process involving FIFA's independent judicial bodies and that the case would be decided in due course by the competent bodies".
