THESSALONIKI, Greece - Sunday's Greek Super League derby between PAOK Thessaloniki and Olympiakos was called off after Olympiakos coach Oscar Garcia was struck in the face by a toilet roll thrown by a spectator minutes before kick-off.
Garcia left Toumba Stadium for a local hospital to seek treatment for a bloodied lip.
The incident prompted the Olympiakos team to leave the pitch in protest before riots erupted outside the ground.
"I took my team and left. Goodbye," angry Olympiakos vice-president and general director Savvas Theodoridis told referee Alexandros Aretopoulos.
However, PAOK communications director Kyriakos Kyriakos said: "It was obvious that Olympiakos came here with that goal (to suspend the match). They have been provoking for 30 years now. They came to scream and to provoke."
Angry PAOK fans leaving the stadium then clashed with police who used tear gas to quell the violence.
PAOK are the league leaders and have a 9-point advantage over third-place Olympiakos who have won the last 7 straight league titles.
Aretopoulos was finishing his report with the match most likely to be officially suspended leading to a possible heavy punishment for PAOK, which may include a loss of points as well as a fine.