Pantelic helps Olympiakos close in on top spot
Serbian striker Marco Pantelic's goal in the 32nd minute gave Olympiakos their second win in three league matches.
The result means Olympiakos are second with six points, with unbeaten Iraklis leading the way with seven points following the Salonika club's 1-0 win over Larissa on Saturday.
AEK Athens missed the chance to join Olympiakos on six points when they were held to a 2-2 draw at home to Asteras Tripolis.
AEK fought back from two goals down, with strikes in the final 10 minutes from Algeria forward Rafik Djebbour and Argentine winger Nacho Scocco cancelling out earlier efforts from Salim Aras and Kostas Fortounis.
Djibril Cisse scored twice for champions Panathinaikos but the side's stuttering start continued as they were held to a 2-2 draw at Kavala on Saturday.
Panathinaikos, who were thumped 5-1 in the Champions League by Barcelona in midweek, went ahead through Cisse after 12 minutes but were stunned when Kavala scored twice in three minutes through Douglao and veteran French striker Jean-Claude Darcheville.
Cisse netted again 11 minutes from time but Panathinaikos now lie seventh after picking up just five points from their first three games.