PAOK capitalised on a rare off-night for Olympiacos to pull five points clear at the top of the Greek Super League.
The Pireaus club dropped valuable points in a goalless draw at Asteras Tripolis a day earlier, meaning PAOK's 2-0 triumph at Ergotelis gave it a very healthy advantage in first place.
Stefanos Athanasiadis (42 and 90) scored both goals in Heraklion.
Sixth-placed Panathinaikos beat Atromitos 2-0 thanks to an own-goal from Nikos Lazaridis (27) and Nikolaos Karelis's 85th-minute strike.
There was a goal fest at Panetolikos, with the host running out a 5-2 winner over Skoda Xanthi.
Christos Lisgaras (four) opened the scoring, but the Canaries soon fought back thanks to Lucas Villafanez, who scored a brace with goals in the 22nd and 45th minutes.
Adrian Lucero equalised just before half-time, but further strikes from William Edjenguele (53), Nicolas Martinez (61) and Leandro Kappel (69) kept all three points in Agrinio.
There were no goals in the games between Niki Volos and Kerkyra and Panthrakikos and OFI, although the team from Crete did endure the late dismissal of substitute Konstantinos Banousis.