Olympiakos have moved to within two points of Greek league leader Panathinaikos after winning 2-0 at PAOK from goals by Djamel Abdoun and Kevin Mirallas.
Abdoun scored in the fifth minute on Sunday and Mirallas found the net in the 18th.
In other games, AEK Athens beat Panionios 1-0 to move past PAOK into third place, and Panaitolikos drew 1-1 with Atromitos.
Aris beat Xanthi 2-0 in a match that was interrupted for more than 30 minutes after lightning struck the stadium, putting the lights out.
Panathinaikos was shocked 1-0 at lowly Levadiakos on Saturday.