A 2-1 win at Paok Saloniki has finally ensured clear conditions: Olympiakos Piraeus is the 47th time Greek champion.
The team of coach Pedro Martins (Portugal) now has 76 points in the account and can no longer be displaced from the top in the remaining four match days of the play-off phase.
It is the third championship in series for Olympiacos under Martins.
Thousands of Olympiac fans celebrated the championship title of their club on the streets of Piraeus, as Greek television showed.
With its 47 titles, Olympiakos is the most successful team in Greece.
All other teams have won 39 titles together.
After Paok took the lead early through the Austrian Thomas Murg (10th), Rony Lopes (51st) and Oleg Reabciuk (62.) turned the skewer in the second round.
The ex -Dortmund and Werderaner Sokratis was in the starting line -up at Olympiacos.