Panathinaikos are eight points clear of Olympiakos in the Super League as the Reds saw their title hopes all by ended by PAOK at the Karaiskaki Stadium.
The Thessaloniki side came away from Piraeus with a 1-0 win that puts it on the same points as Olympiakos.
At the same time PAO drew 0-0 with fourth-placed Aris away and are clear favourites to win the title.
If Olympiakos chairman Sokratis Kokkalis thought that firing Zico would fix all the problems at his club, he found out on Sunday that this is not the case.
The Reds were outclassed by an in-form PAOK who scored in the first-half through on loan striker Edinho at the end of a brisk counter-attack.
The visitors could have won by a wider margin but struck the post twice in the second half, so Olympiakos were spared further humiliation.
Their fans, however, did not see it this way and booed the players off the field at the end of the 90 minutes and also chanted slogans criticizing Kokkalis.
The result means that PAOK and Olympiakos have 40 points after 19 games.
Panathinaikos are on 48 points after a goalless draw at Aris’s Kleanthis Vikelidis Stadium.
In a game of few clearcut chances, one of the best opportunities fell to Fulham striker Eddie Johnson, but the on loan American saw his effort saved spectacularly by PAO’s Alexis Tzorvas.
The draw means that Aris have 32 points and are three points clear of fifth place.
With 11 games left, the title now appears Panathinaikos’s to lose despite the fact that Nikos Nioplias six-match winning streak since he took over came to an end on Sunday.
AEK are sixth on 29 points after beating PAS Yiannina 3-1 at home thanks to a brace from Pantelis Kafes.
Another notable result on Sunday was Panthrakikos’s 1-1 home draw Xanthi, which was just the third point that the club from northeastern Greece has picked up all season.
In the day’s other game, Atromitos beat Kavala 2-0 at home to continue its recent run of good form, which has propelled the Athenian side to seventh place with 26 points.
In a potential relegation battle on Saturday night, Larissa achieved an important victory in their ‘six-pointer’ with Iraklis, while there were also wins for Asteras Tripolis and Ergotelis.
Larissa and Iraklis went into the game at the Alkazar Stadium knowing that a win for either one would put some distance between them and the bottom three.
It was no surprise then that the first half proved to be a tense affair. But the second 45 began in the best possible way for the home side as Brazilian striker Ricardo Jesus, who joined on loan from CSKA Moscow this month, opened the scoring almost straight from the kick off.
Another Brazilian, Romeu, made it 2-0 just before the hour mark to set Larissa on their way.
Youngster Dimitris Yiantsis pulled one back for the visitors in the 77th minute with a wonder strike but it proved to be little more than a consolation goal for Iraklis who are just one place and one point above the relegation zone with 19 points from 19 games.
Larissa have moved up to 11th place with 21 points.
Ergotelis are sitting comfortably in mid-table after a 1-0 win over Levadiakos who remain second from bottom and are almost certain to go down.
Dimitris Orfanos scored the only goal of the game in the second half.
Asteras Tripolis have moved up to fifth with 29 points after a valuable 2-0 win over Panionios at home.
Both of the home side’s goals came from Argentinean midfielder Lucas Daniel Willchez in the first half.
Panionios are in a run of bad form, not having won a game since December 6 and their problems were compounded in injury time when Fabian Estoyanoff was give a straight red card for a dangerous tackle.