The fixture - known as the derby of eternal enemies - has a long history of violent clashes between the two sets of supporters.

And as Olympiacos players warmed up ahead of the game at the Stadio Apostolos Nikolaidis, home fans invaded the playing area and attempted to get at them.

The players were able to escape down the tunnel to safety before police eventually were able to restore order, and the match kicked off around 15 minutes later than originally scheduled.

When it did commence, there was more trouble at the start of the second half as a flare was fired into the away dugout.

Panathinaikos went on to win the game move within three points of their arch-rivals at the top of the Super League.

After a goalless first half Arthur Masuaku gave Panathinaikos the upper hand by putting through his own net in the 49th minute, with Mladen Petric doubling the' advantage with 12 minutes remaining.

Substitute Alejandro Dominguez halved the deficit for Olympiacos on the stroke of full-time but it was too little, too late, for Vitor Pereira's men.

Olympiacos president Vangelis Marinakis brandished the actions of Panathinaikos fans as an "atrocity".

The fixture has a long history of violent clashes between the two sets of supporters, and Marinaikos was stunned to witness the scenes.

"Unfortunately today we saw an atrocity for Greek football," he said.

"What we saw today I don't think think I had ever imagined.

"I cannot deny that I'd be the first to give congratulations to Panathinaikos, but today they only deserve sympathy.

"Our players cannot play well in these conditions and are heroes. It is unprecedented.

"I saw the players. Others are beaten, others are upset, others are shocked.

"We did not come for war, we came to play football."

Asteras Tripoli thrashed OFI Crete 6-1.

Jeronimo Barrales (four, 41 and 79) scored a hat-trick, with Pablo Mazza (45 and 66) netting twice before substitute Facundo Parra chipped in with a 90th-minute goal.

Crete did manage to blot Tripoli's clean sheet with Andreas Lampropoulos' 88th-minute penalty.

Evangelos Oikonomou boosted Panionios to a 1-0 victory over Levadiakos while Abdul Aziz Tetteh and Fabinho exchanged goals in a 1-1 draw between Platanias and Kerkyra.