Saturday's derby between hosts Panathinaikos and Olympiacos was called off after home fans clashed with police.
Olympiacos players were pelted with missiles as they came out for their pre-match warm-up - reports suggested Olympiacos striker Alfred Finnbogason was injured after being hit.
Police attempted to quell the disorder, but that only resulted in running battles in the stands, prompting referee Andreas Pappas to postpone the fixture before kick-off. The violence continued in the streets as angry fans poured out of the ground.
Fans and police had earlier clashed outside the Apostolos Nikolaidis stadium as ticketless supporters attempted to gain entry. One police officer is reported to have been taken to hospital with a head injury.
Olympiacos top the Super League table with 30 points thanks to a 100 per cent record after 10 games. They are eight clear of second-placed Pana.