Panathinaikos beat Atromitos and AEK defeated PAOK on Wednesday for the Super League playoffs to set up what will essentially be a final for a place in next season's Champions League on Sunday.
Panathinaikos will be Greece's second representative in the continent's top club competition if it avoids defeat at home to AEK, as it has a two-point lead over its cross-town rival.
On Wednesday the Greens needed a second-half strike by Sotiris Ninis to beat Atromitos 1-0. It was spectacular shot in the 65th minute that settled the game and will have boosted the morale of Ninis after a string of injuries that had put his place in the national team in jeopardy.
AEK made it three wins in as many home games in the playoffs as it defeated nine-man PAOK 2-0 at the Olympic Stadium.
Nikos Liberopoulos made the most of a poor clearance by PAOK keeper Costas Chalkias to score in the 33rd minute, with Leonardo doubling AEK's tally five minutes from time.
Pablo Garcia and Giorgos Fotakis were sent off for PAOK.
With just one game left, Panathinaikos has 11 points, AEK is on nine, PAOK has seven and Atromitos is last with five points. On Sunday Panathinaikos hosts AEK and PAOK greets Atromitos.