Iraklis was relegated from the Basket League on Saturday, as it could not beat Panathinaikos, while Peristeri snatched the last play-off spot with its win over Lavrio.
The last round of games in the regular season condemned Iraklis to its exit from the top flight, as despite its brave effort at home against Panathinaikos, staying level up to 47-47, the Greens made their quality tell to win 81-59 in the end.
That meant Ionikos managed to stay up, despite its 86-84 loss at Larissa. The hosts, that finished sixth, had Stefan Moody score seven triples in the first half and 35 points overall.
Olympiakos has topped the table and will have home advantage throughout the play-offs. On Saturday it defeated third-placed Kolossos Rhodes 93-74 in Piraeus.
Peristeri sneaked into the play-offs with its 91-80 home win against last season’s finalist Lavrio.
In other games on Saturday, PAOK saw off AEK with a 96-72 result and Apollon celebrated its staying up with a 74-73 victory over Aris in Patra.
The pairings for the best-of-three play-offs are as follows: Olympiakos vs Peristeri, Panathinaikos vs Aris, Kolossos vs Larissa and AEK vs Promitheas Patras.