Ronald Burrell had 20 points and 12 rebounds and EWE Baskets shot very well at the free-throw line in a 77-69 win over BK Ventspils in Germany.
Unbeaten in the Regular Season, EWE Baskets prevailed in the Group I clash for the seventh consecutive game in the competition.
Predrag Krunic's team got a defensive lift from Kenny Hasbrouck, who had five of the team's eight steals.
He and Ricky Paulding scored 15 points apiece.
EWE Baskets made 19 of their 22 free-throws compared to Ventspils' 12 of 22 effort.
The home side led from start to finish but were only on top 30-27 at half-time.
After Paulding began the second half with a lay-up, Ventspils pulled to within 32-30 on a three-pointer from Arturs Berzins.
The hosts then hit their Latvian opponents with a flurry of blows they would not recover from.
Hasbrouck drilled a three-pointer and made a lay-up before Adam Chubb scored down low.
Burrell followed with a jumper and drew a foul.
He sank the free-throw for the three-point play to cap the 10-0 run.
EWE Baskets stretched the advantage to 61-39 late in the third quarter.
They ended up outscoring the visitors, 31-15, in the frame.
Ventspils, mindful that goal differential could be a determining factor if a tie-breaker is needed at the end of Last 16 play, battled and reduced the deficit to eight by the end of the contest.
The 20-year-old Latvia international center Martins Meiers had 23 points and seven rebounds in defeat.
Predrag Krunic (coach EWE Baskets):
"Congratulations to my team. It is always important to win the first game in a new round, to stay confident. I was very satisfied with our defense today. We had a very good start to the game and to the second half, when we played with a lot of pressure and I think that was the reason why we left the court as winners. Even foul problems and injuries didn't affect our gameplan."
Gundas Vetra (coach BK Ventspils):
"Congratulations to Predrag Krunic and his team. We had two bad phases today - the beginning of the game and also the start of the second half broke our neck. Overall i don't think we played a bad game, in the fourth quarter we even had chances to get back into it. But in the end Oldenburg deserved the win."
Robin Smeulders (player, EWE Baskets):
"This was a very good win for us. It was by far not an easy game and Ventspils played with a lot of passion. We played very good under the basket and after Bobby Brown went out with an injury the whole team stepped up and compensated for the loss.This win gives us a lot of confidence going into the next away games."
Steven Gray (player BK Ventspils):
"Coming into this game we knew that Oldenburg had a very good team and that their fans would create a highly emotional atmosphere. We wanted to keep the game close, but in the third quarter they built too much of a lead. We really fought to get back into the game and were one run away from making it a close contest. I still like our chances to qualify for the quarter-finals if we keep playing consistently."