Hours before a clash that leaves little room for calculation, Georgios Donis and his staff are sweating on the fitness of one of their key attacking men ahead of the eagerly anticipated meeting with Qatar.
Saudi network Al Arabiya report that Zakaria Hawsawi is nursing a severe bruise to the knee. The problem has thrown his involvement against Qatar into doubt, with medical tests set to determine whether he can carry on with Saudi Arabia in the next stage.
Hawsawi trained in the swimming pool today, part of a programme designed to manage the injury. He faces a fresh test tomorrow as the medical staff try to pin down just how serious the problem is and how far it hampers his movement and availability.
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That test will see Hawsawi walk on the injured foot so the medical staff can gauge how much pain he feels on the move, before the final call is made on whether he can face Qatar.
Donis now faces losing one of his most important options. The clock is against him, and with so little time before kick-off, there is scant room to gamble on a player whose physical readiness will decide whether or not he makes the squad.
Tomorrow's test settles it. The coaching and medical staff will either clear Hawsawi to keep preparing for the game or rule him out if the pain lingers, making the coming hours decisive in whether Donis's attacking key man takes his place in the battle between Saudi Arabia and Qatar or sits it out through injury.