A linesman suffered a head injury when an object was thrown at him during Thursday's Europa League clash between Sturm Graz of Austria and AEK Larnaca from Cyprus, the Austrian club said as it condemned the attack.
"This behaviour is completely unacceptable and damages the reputation of football and of our club," said Graz on its website after they had lost the first leg of the third qualifying round tie 2-0.
The linesman was hit and fell to the ground in the 78th minute of the game with blood pouring from his head.
After being treated by medics, he walked to the dressing room with his head bandaged.
Sturm Graz added that the fan who threw the missile had been apprehended.