Greek Super League leaders Olympiakos Pireaus extended their advantage over Panathinaikos to four points with a 3-0 win over Aris Salonika as their title rivals slumped to a 2-0 derby loss to AEK Athens on Sunday.
First-half goals from Ivan Marcano and Jose Holebas from the penalty spot put Ernesto Valvede's Olympiakos firmly in control, before Belgium striker Kevin Mirallas netted his 14th goal of the season to seal a 10th consecutive win in all competitions for the champions.
Aris had Greece goalkeeper Michalis Sifakis dismissed on the stroke of half-time for a professional foul on Mirallas.
Olympiakos moved on to 58 points from 24 matches and are also well placed to progress in the Europa League.
The Red and Whites face Metalist Kharkov at home in the second leg of their Round of 16 tie on Thursday with a 1-0 lead to protect.
"Nothing is finished yet and we want to continue like this until the end of the season," Valverde told reporters.
"We have difficult matches ahead of us and if we want to be champions we have to keep our current form going."
Olympiakos' win meant that all the pressure was on Panathinaikos to pick up three points in Sunday's late derby match at the Olympic Stadium but Jesualdo Ferreira's team were well beaten.
The Greens, without injured top scorer Sebastian Leto, fell behind after 48 minutes when goalkeeper Orestis Karnezis failed to keep out a long-range free-kick from AEK's Brazilian forward Leonardo.
Panathinaikos threw players forward in search of an equaliser but were caught on the break with 19 minutes left when AEK substitute Victor Klonaridis raced clear to drill the ball home.
With just six matches of the season remaining, next weekend's derby meeting between the top two at the Olympic Stadium could prove decisive in the title race.