Champion PAOK unexpectedly dropped two points last Sunday at the club it is alleged to share the same owner, Xanthi, and finished the regular season of the Super League seven points behind leader Olympiakos.
The Reds will therefore need eight wins in the 10 games of the playoffs to clinch the title. The playoffs begin on March 7.
Undefeated Olympiakos – fresh from shocking Arsenal in London for the Europa League – saw off struggling Panetolikos 2-0 at home, goals coming from Giorgos Massouras and Andreas Bouchalakis.
PAOK drew 1-1 at Xanthi, as the Chuba Akpom goal for the champion was answered through an equalizer by Christos Lisgaras.
AEK, in third, needed an an injury-time strike by Viktor Klonaridis to escape defeat to Panionios (1-1) at Nea Smyrni from the Dimitris Emmanouilidis goal.
Panathinaikos had no problems against visiting Volos, thrashing its 10-man opponent 4-1 with two goals from Federico Macheda and one each by Dominik Nagy and Tasos Hatziyiovanis. Volos pulled one back through Erik Jendrisek.
Atromitos upset Aris with a 2-1 win in Thessaloniki to allow OFI, victor of Lamia with a 3-0 score on Crete, to finish the regular season on fifth, level on points with sixth Aris.
Larissa had Radomir Milosavljevic score a hat trick in its 3-0 home victory over Asteras Tripolis.
The home-and-away round-robin playoffs for the top six teams, to determine the title and the Greek tickets to European competitions next season, will be contested by Olympiakos starting from 66 points, PAOK (from 59), AEK (51), Panathinaikos (44), OFI (34) and Aris (34).
The playouts will consist of seven rounds of games, with teams that finished from the seventh to the 10th spot (Atromitos, Asteras Tripolis, Larissa and Xanthi) playing four times at home and three away, and the last four (Lamia, Volos, Panetolikos and Panionios) playing three times at home and four away.
The last team will go sown to Super League 2, while the team just above it will contest a playoff with the team to finish second in Super League 2.