The German team improved to 3-3 with the victory and finished behind Cholet (5-1), while Belgacom slipped to 2-4.
Earl Jerrod Rowland poured in 22 points for Bonn, who trailed 52-47 with 8:09 remaining in the game.
A three-pointer from Moussa Diagne sparked a 9-0 Telekom Baskets run as they claimed the lead.
Belgacom weren't finished, with Christopher Hill making a three-pointer to knot the scores at 56-56 with 2:57 remaining.
Rowland went to the other end and made a three for Bonn and they outscored the home side 11-3 over the last 2:28 of the game.
Will Thomas finished with 11 points and nine rebounds for Belgacom.