EWE Baskets Oldenburg had a much tougher game on their hands the second time around but still defeated U-Mobiltelco 77-72.
Tuesday's triumph gave the German team a 163-132 victory on aggregate in the EuroChallenge Round 1 and put them into next phase of the competition.
Oldenburg, playing in Europe for the first time, had won the first leg 86-60. They trailed 42-36 at half-time of the second leg but were never under serious threat of blowing their aggregate lead.
Nevertheless, Tab Baldwin's Cluj team were still in front at 69-68 with four minutes remaining before being outscored 9-1 over the last 3:30 of the contest.
Babmale Osby of Cluj had 18 points and six rebounds, and he said: "We played with more energy than in game one.
"The atmosphere in Oldenburg and our whole trip was a nice experience for me and my teammates.
"Our goal was to play better than in Cluj and to keep the score close. I think we succeeded in doing so."
Rickey Paulding Jr finished with 19 points and 13 rebounds for EWE Baskets.