Olympiakos celebrated winning the Greek league for a 44th time on Sunday, but they may still miss out on the title.
A hearing on Tuesday will decide what punishment the club will receive over crowd trouble after a Greek Cup semi-final first leg defeat by AEK Athens.
The Piraeus club are six points clear of PAOK with one match left, but they could still get a six-point deduction.
If that were to happen, PAOK would go top if they won their last match of the season and Olympiakos lost theirs.
PAOK, who have won the league just twice before, the most recent time in 1985, have the better head-to-head record.
Goals from ex-Chelsea winger Marko Marin, Manuel Da Costa, two from Alberto de la Bella and an Alejandro Dominguez penalty earned a 5-0 home win over Giannina on Sunday.
“It has been a strange season but in the end we’re the champions and that’s what matters,” Olympiakos coach Takis Lemonis said after the game.
His side play 11th-placed Panaitolikos in their final match of the season next Sunday, when PAOK play 10th-placed Kerkyra.