Olympiacos defeated bitter rival Panathinaikos 1-0 in the Greek Super League but still trails PAOK after the latest round of matches.
Substitute Anastasios Avlonitis scored on 59 minutes, just two minutes after coming on from the bench, to give Olympiacos a home victory over Panathinaikos at the Karaiskis Stadium.
PAOK maintained top spot thanks to a 4-1 win over Veria.
Robert Mak (25), Dimitris Salpingidis (42), Ergis Kace (57) and Stefanos Athanasiadis (79) all scored for PAOK, with Ben Nabouhane's 83rd minute goal not enough for the visitor.
Elsewhere, OFI Crete fell to a 3-2 home defeat by Asteras Tripoli on a day when former AC Milan and Rangers midfielder Gennaro Gattuso quit his role as coach of the Crete side, according to reports.
"It's difficult for me to continue this experience. I put passion and strength into this and I'm sorry, but I cannot continue," he was quoted as saying in the Greek press.
"I spent four incredible months in a marvellous city with wonderful fans. I cannot continue to carry this situation on my shoulders alone."
The 36-year-old's managerial career has been a chequered one so far. He lasted 11 games with Swiss side Sion, six with Italian club Palermo and now only seven league matches with OFI.
Fernando Usero's 10th-minute penalty opened the scoring for Tripoli before Carlos Milhazes (53) levelled. Pablo Mazza (58) and Anastasios Tsokanis (63) then put the visitor ahead, with Giorgi Merebashvilli's 88th minute goal not enough for the host.
Meanwhile, Thomas Nazlidis (penalty) and Juan Aguilera (58) scored as Platanias claimed a 2-1 win at Kerkyra, with Marko Markovski (26) scoring for the home side.
Erick Moreno scored a hat-trick as Panetolikos defeated Panthrakikos 3-1.
Moreno (13, 74pen, 86) scored all three for the hosts, while Jose Maria Cases (60) scored Panthrakikos' only goal of the game.