Panathinaikos ended Olympiakos' 27-match unbeaten league run on Sunday with a stormy 3-0 away victory that was interrupted for long stretches by home fans who threw flares and other objects onto the pitch.
After the game, Olympiakos fans took their frustration out on riot police, attacking them with whatever projectile was available. A police motorcycle was set on fire and police used tear gas to disperse the crowd.
During the match, Panathinaikos coach Yiannis Anastasiou was hit in the face by a plastic cup full of liquid and ice cubes. Very little football was played in the last 12 minutes due to the missile-throwing after Olympiakos was awarded a penalty.
"I feel a little dizzy, but I'm otherwise fine," said Anastasiou, who compared the hostile atmosphere of Sunday's match to that of Olympiakos' home victory over Manchester United in the Champions League.
"I saw Tuesday's game ... and marvelled at the fantastic atmosphere. Now, we have reverted back to our usual culture, where we (away teams) are not sure we will leave the field in one piece. What can I say," added Anastasiou, who had a bandage over his left eye.
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Alejandro Dominguez missed the spotkick four minutes after it was awarded and the referee didn't make up for time lost.
In a separate incident, Olympiakos' Michael Olaitan collapsed in the 30th minute and lay unconscious on the field for some time while being treated by both teams' doctors. He was taken to hospital for checks, and was conscious when taken off on a stretcher.
An Olympiakos official told TV channel Novasports after the game that Olaitan had injured his neck when falling on the pitch, but that he was feeling better.
During the game, Panathinaikos packed the midfield and tried to hit Olympiakos on the break - a tactic that produced the visitors' first two goals. In the 45th, a long pass found Marcus Berg inside the area and he laid the ball back for Danijel Pranjic to score with a drive from just outside the area.
In the 67th, another long ball found Berg on the break and he outsprinted defender Avraam Papadopoulos before shooting past goalkeeper Roberto.
In the 89th, when the game had temporarily resumed, Panathinaikos won a free kick on the left side and Mehdi Abeid found a gap in the wall to beat a motionless Roberto. Immediately afterward, a volley of flares had Panathinaikos goalkeeper Stefanos Kapino fleeing his own area for his safety.
"Nothing turned out well for us today," said a despondent Michel, the Olympiakos coach.
Olympiakos midfielder David Fuster added: "We did not play like we should, but we should not linger over this. It was a bitter moment in an otherwise very good season."
Indeed, even after losing to its hated archrival, Olympiakos still has a 19-point lead with seven rounds remaining and is well on its way to winning a record 41st league championship, its 16th in 18 seasons, starting in 1996-97.
Closest challenger PAOK squandered a 2-0 lead and allowed host Ergotelis to earn a 2-2 draw. This enabled Atromitos, a 3-1 winner at Panetolikos, to go level on points with second-place PAOK. Panathinaikos is fourth, five points behind Atromitos and PAOK.
