A linesman went down injured in a Europa League clash between Sturm Graz and AEK Larnaca, as the matches descended into havoc.
Swedish assistant referee Fredrik Klyver went down with an injured head and later required several stitches after a beer cup was thrown from the stands.
Klyver then left the pitch in a bad way, a bandage around his head, while a fourth official had to come in to replace him.
Side Sturm Graz, who lost 2-0 with the game ending early, apologised for actions of the supporters, who ran out of the stadium quickly but was later caught.
"This behaviour of a fan in today's Uefa Europa League game is by no means acceptable,' a statement from the club said.
"This damages the reputation of football and us as a club. 'We always try to see football as a positive celebration and to tackle these things. Fair play is our top priority. We are sorry that today we have disappointed many football fans."
"The cup thrower was caught. The possible punishments will be considered. 'Sturm Graz wishes the linesman all the best and speedy recovery."
We hope that the referee gets the proper treatment. It's not the first time a referee has been assaulted while doing his job and it won't be the last.