Egypt coach Hossam Hassan cast doubt on whether talisman Mohamed Salah will start their World Cup last-32 showdown with Australia on Friday in Texas following a hamstring problem.
Salah took part in training with the rest of the squad in Dallas on Thursday, albeit a lighter session in front of the cameras.
The 34-year-old former Liverpool superstar was forced off the pitch in the 57th minute of Egypt's final group game, a 1-1 draw with Iran a week ago.
The striker placed an icepack under his left thigh, throwing his participation against the Socceroos in doubt.
"We tried to introduce him to partial training yesterday only," Hassan said on Thursday, the eve of the match at the home of the Dallas Cowboys.
"He is very much looking forward to making his own contribution tomorrow.
"On the other hand, I am not going to run any risk unless I am 100 percent sure he is fit and raring to go tomorrow.
"Not so sure if he will be in the starting line-up."
Egypt are looking to make more history for their country in Texas.
They earned the first World Cup win in their history by beating New Zealand 3-1 in the group phase.
Hassan said he was wary of the height and pace of Tony Popovic's Australia, especially when it comes to set-pieces.
Neither Australia nor Egypt have ever won a World Cup knockout match.
"We are well prepared to deal with everything we will face," said Hassan.
"We have been working hard for more than two years now with our style and personality.
"It is more than one player, it is a collective, and we aim to showcase this tomorrow.
"We aim to bring joy to our people, to Africa and to the Arab world."
Powerhouses of African football with a record seven continental titles, Egypt struggled to make a dent on the global stage in three previous World Cups.