Panathinaikos seemed to be in control of the game against Hapoel Tel Aviv, but their collapse in the final quarter left them exposed.
The Israelis' 23-8 run resulted in an 92-88 defeat in "green" Sofia, complicating their path to the top six.
Dimitris Giannakopoulos spoke after the "Greens'" defeat, expressing gratitude to the fans who supported the team with their presence in Bulgaria and with the season ticket sell-out.
In detail
"What a shame for the 6,000 who went to support... What a shame for the new season ticket sell-out and everyone who believes in us. A big personal thank you to everyone."