BK Pardubice took the inside track to the Last 16 from Group C by downing visiting Czech rivals BK Prostejov on Wednesday.
Maurice Hampton poured in 22 points and led Pardubice to a 98-84 triumph to leave both sides with 3-2 records.
Because Pardubice have a superior goal differential in their two meetings, they will advance with a victory over BC Goverla (0-5) next week.
Prostejov must travel to Roanne Basket (4-1) for their last game. Should they win and Pardubice fall, then Prostejov would advance.
Pardubice led by as many as 13 points in the opening frame.
Hampton's three-ball made it 29-16 with 27 seconds to go in the period.
The advantage ballooned to 53-35 by half-time when Hampton went in for a lay-up just four seconds before the break.
The lead reached 57-37 after Marcus Arnold made a lay-up early in the third quarter.
Prostejov reeled off 11 unanswered points to close the gap to 57-48, only for the hosts to go back in front 67-48 on a lay-up by Corey Muirhead.
Pardubice's lead never dipped below 13 in the last quarter as they clinched a hugely important victory.
Arnold and Muirhead each had 18 points for Pardubice.
Arvydas Eitutavicius had 21 points in a losing effort.
Prostejov Head Coach Zbyněk Choleva
"I want to congratulate the home team. With us it was completely opposite story. Just as they had a good game we had a bad one. We did not play good defense, we did not rebound. And additionally we had an inability to score. We had received more than fifty points in the first half and then it is hard to play. We definitelly wanted to start the game better. We even changed the starting lineup for that. That's because we wanted to pressure them more. But it worked only for a while. I did not recognize our team today at all."
Pardubice Head Coach Jan Slowiak
"I have to thank my players. I think we showed good basketball and the potential we have. I think we showed that we are serious about the ambitions we proclaimed before the season. I am glad that we kept a real chance to make it to the Last 16 in Eurochallenge. One of the key moments was that we played uptempo basketball. We scored easy baskets on the fast break. And also very important factor was that we won the battle on rebounds. Second chances were big for us and on the other side we did not allow many to Prostějov. We played good team basketball and we were better team today."
Prostejov player Travis Peterson
"It was an important game. We came here to win. We came out with lack of energy. I want to congratulate Pardubice and we want to prepare for the next game in France and we are going to hope that we will win over there."
Pardubice player Maurice Hampton
"I think it was important to get off to a good start, to have the confidence throughout the game. We fell twice this season against Prostějov. So we had a lot of motivation. We were able to keep the game at the high pace. And it was important to have rebounds in this game."