Steaua-Turabo Bucharest used a big scoring burst midway through the opening quarter as a launch pad for a 72-59 victory in Group F against Enterprise BC Dynamo.
Beaten by the visitors from Russia in the first meeting, Steaua-Turabo trailed 14-10 when reeled off 12 straight points.
They had a 25-16 lead by the end of the opening quarter and stayed in front the rest of the way, ultimately claiming a 13-point triumph to improve to 2-2 and drop Dynamo to 1-3.
Steaua-Turabo are level with Antwerp Giants, who crashed to a heavy defeat at Lokomotiv Kuban earlier Tuesday.
Virgil Stanescu had 21 points for the Romanian side, which got nine boards from Dumitru Carutasu and won the rebounding battle, 34-25.
They also forced Dynamo to turn the ball over 22 times.
The Russian team actually shot better from long range (seven of 13, 53.8%) than they did from inside the arc (11 of 26, 42.3%).
Vasily Zavoruev had 14 points, including a four-of-six night from three-point land, to lead Dynamo.
Steaua Turabo Head Coach Teo Cizmic:
"Great victory in front of beautiful crowd who supported us perfectly. Winning against any Russian team is big success and I think that in the last 15 days we did our homework. From the time I am the coach here this was the best defense of my team. Congrats to my guys and I hope this will give us courage for next games. The only thing that I regret is the injury of Popescu, a broken nose, Lucic, Carutasu and Tibirna."
Steaua Turabo player Virgil Stanescu:
"It's great to see a team like this on the court, Steaua Turabo. Not many people gave us a chance after the loss in Moscow. I am glad to see a lesson learned and I am happy for all the players in my team, that we showed we can also play in Europe. This win gives us hope, showing us how much we improved and that we are on the right track to become a great team. We still have much to change but we will worry about that tomorrow and today will celebrate a great win over a Russian team."