Belgacom Liege finished EuroChallenge Group A a perfect 6-0 but only just as they were taken to the wire by last-placed Energa Czarni on Tuesday night.
Justin Cage scored the last of his game-high 22 points as time expired to eke out a 93-91 win.
Liege were up 86-78 with 3:38 to go, but Czarni then launched a rousing comeback bid, with Marcin Srorka's three-pointer sparking a 10-0 run that turned the game on its head.
After Christopher Hill came up empty on a three-point attempt for Liege, Czarni took the lead when Marcin Dutkiewicz nailed a long-range attempt with 1:17 to go to make it 88-86.
Cage had a chance to tie it from the free-throw line but missed the second of his two shots to leave the gap at one.
But Demetric Bennett then missed a jump shot for Czarni and Will Thomas made them pay with two from the charity stripe to put the visitors back in front at 89-88 with 53 seconds to go.
Thomas then made it 91-88 with a dunk, but Bennett replied with a three-pointer that tied it 91-91 with 13 seconds to go.
Liege then drew up a final play, and Cage hit a jump shot as time expired to claim the win.
Cage finished with 22 points to lead five players scoring in double figures for Liege.
Jamar Wilson had 20, Larry Owens 17, Thomas 15 and Hill 11 for the victors.
Czarni finished with six players scoring in double figures. Mantas Cesnauskis had 20, Bojan Bakic 18, Sroka 14, Bennett 12 and Mateo Kedzo and Pawel Malesa had 10 each.
Gasper Okorn, Energa Czarni Coach:
"We treated this game as a practice but of course I am sad that we couldn't win. I am more and more satisfied with my team's offense, which is more aggresive. If we can play with the style from last two weeks in every game, this season would not be lost for us."
Tom Johnson, Belgacom Coach:
"I think the Slupsk team played better in offense and they should have won this game. But I am happy this night was ours. It is very difficult to play with small arenas where fans are loud and atmosphere very hot."
Justin Cage, Belgacom Player:
"I knew it would be very difficult game. I am happy that my teammates and I were able to win this."
Pawel Malesa, Energa Czarni Player:
"At last our play looks so much better. We have new players coming, they will be able to play league games, and our team with them will be even better."