Fifa has rejected an appeal from Portugal to have Cristiano Ronaldo's yellow card rescinded.
The Real Madrid winger was booked during a 0-0 draw with the Ivory Coast on Tuesday and is now walking a disciplinary tightrope.
Were he to be cautioned again during Portugal's game against North Korea on Monday he would be forced to sit out a crunch clash with Brazil four days later.
That contest could yet determine the fate of Carlos Quieroz's side, with qualification for the latter stages far from certain.
As a result, Portugal had hoped to see the appeals panel let Ronaldo off the hook and spare him from the threat of suspension.
However, Fifa have given their backing to the match officials and have made it clear that the decision will not be reversed.
"We have been told by Fifa it has rejected the appeal," said a Portugal spokesman.
"It said it was not an error of fact, which happens for example when the wrong player is booked, and was at most an error in relation to the rules.
"In these cases the referee is sovereign, so Fifa has rejected our appeal."
Ronaldo saw yellow after becoming involved in an off the ball altercation with Ivory Coast full-back Guy Demel.
He did not appear to do much wrong, as he was surrounded by opponents, and his fellow midfielder Raul Meireles has hit out at Fifa for failing to revoke the decision.
"Cristiano is an important player for us," he said.
"It was a situation in which he did absolutely nothing and got a yellow, and it's that type of yellow card that hurts the most."
While refusing to come to Ronaldo's aid, yellow cards are an issue Fifa have been looking into.
They are keen to ensure that no player is forced to miss the final through suspension and as such have put a ruling in place which will see all card counts wiped clean at the end of the quarter-final stage.
That means only a red card in a last four encounter would force a player to miss the showpiece game in South Africa.
Spokesman Marius Schneider said: "Fifa simply said we want to give the best players a chance to play in the final. The discussion first came up when Ballack was ruled out (in 2002)."