Bulgaria did Belgium a huge favor on Saturday by upsetting Serbia but the Belgians failed to take advantage in Greece.
Needing to win to leapfrog Serbia into second place, Belgium were blown away 79-40 with Evanthia Maltsi pouring in a game-high 30 points for the winners.
With Greece trailing 6-5, a Maltsi three-pointer sparked an 11-0 run that put her side in front for good.
When Maltsi drilled a three-ball at the end of the opening quarter to raise her points haul to 14, the Greeks were on top 26-10.
They took a 43-24 lead to the changing rooms and had a 62-33 stranglehold on proceedings by the end of the third quarter.
Maltsi ended up hitting six of seven (85.7%) shots from long range.
Evelien Callens finished with 14 points for Belgium, who were out-rebounded 43-30.
Belgium still hope to have a ranking that is high enough to play in the Additional Qualifying Round.