Defender Ivan Marcano scored the only goal of the game for Ernesto Valverde's reigning champions at the Georgios Karaiskakis Stadium as the Reds moved on to 36 points from 15 matches.
Spanish striker Toche scored in injury-time to earn Panathinaikos, who are second with two games in hand, a 1-1 draw at Panaitolikos Agrinion after Henri Camara sent the home side ahead in the 63rd minute.
Panathinaikos had to play the final 11 minutes with 10 players when Jean Alain Boumsong limped off injured after coach Jesualdo Ferreira had made all three substitutions.
PAOK Salonika put financial worries aside to move up a place to fourth thanks to a 3-1 win over struggling Levadiakos, with Vladimir Ivic opening the scoring in the first half and striker Stefanos Athanasiadis taking two more after the break.
The Salonica club have shipped out Portuguese winger Adelino Vieirinha to German club Wolfsburg and Chile international defender Pablo Contreras to Colo Colo this week in a bid to cut reported debts of 9 million euros.
Both players were instrumental in PAOK finishing top of their Europa League group, defeating Tottenham Hotspur at White Hart Lane and setting up a Round of 32 clash with Udinese.
Third-placed AEK Athens lost ground after a goalless draw at home to Doxa Drama, who took only their second point in nine games.
AEK were the second team after Panionios to fail to beat newly-promoted Doxa, with the visitors coming closest to a goal after hitting the woodwork early in the second half at the Olympic Stadium.
AEK have 29 points from 15 games.
Panionios defeated Asteras Tripolis 2-0 through goals by Dimitris Kolovos and Fanouris Goundoulakis.
