CSK-VVS Samara needed overtime on Tuesday but finally put paid to PAOK and did severe damage to their hopes of reaching the EuroCup quarter-final stage.
A pair of Jason Rowe free throws with three seconds remaining tied the game at 63-63, but the visitors from Russia, sparked by Israeli international Yaniv Green, outscored PAOK 10-2 in the extra period and recorded a 73-65 triumph.
The setback has left PAOK 0-3 in Group A and needing to win their remaining three games to have an outside chance of progressing. The Samara club, meanwhile, improved to 2-1.
Green had 25 points and 14 rebounds to pace Samara.
|Alex Scales contributed 24 points to Samara's important win in Greece|
He scored six in the overtime to cap a performance that could go down as the best of the week once all the EuroCup games have been played.
PAOK got a shot in the arm from Turkish great and recent signing Ibo Kutluay, who scored 16 points.
When Kutluay buried a three-pointer with 3:13 remaining in the third quarter for a 46-39 lead, PAOK looked as if they might win the important game in front of their home fans.
Another three-ball by Kutluay extended the advantage to 51-41 with 1:01 remaining in the period.
The Greek outfit weren't able to press home the advantage, though, with an Alex Scales long-range shot 4:50 from the end putting the visitors into a 55-54 lead.
That basket took Scales' points haul to 19, and he would go on to finish with 24.
Kutluay responded with another three-ball to bring the PAOK fans to their feet, but Scales drilled another as well with 3:03 to go to put Samara back in front at 58-57.
After Marque Perry took the score to 62-59 with a pair of shots from the stripe, Rowe drew a foul and made the first of his attempts from the line before missing the second.
He grabbed the offensive rebound and teammate Georgios Tsiakos would end up getting fouled. Tsiakos made just one of two.
Perry then split two more at the line for CSK-VVS Samara, and Rowe earned another trip to the line and made both free throws to send the game to overtime.
But PAOK weren't able to cope with the power of Green as Samara finally pulled away.
PAOK will be kicking themselves after making just nine of 20 (45%) from the line on the night, compared to 18 of 26 (69.2%) for the visitors.