On the road at Eisbären Bremerhaven, Bonn prevailed 75-71 after getting 17 points from Alex King, 16 from Nic Wise and 15 from Chris Ensminger.
A Wise basket with 8:23 to go put Bonn in front to stay at 62-60 but the Polar Bears made sure the game went to the very end.
Another big shot was made by King with just 51 seconds left.
|Andrius Slezas and Prostejov are doing well in the Czech league|
Craig Callahan had just scored to close the gap to 69-68 when King caught a pass from Wise and drilled a three-ball for a 72-68 lead.
After Callahan scored again to cut the deficit to 72-70, Jeremy Hunt split a pair of free-throws for Bonn and they ended up claiming a four-point win.
"Compliments to my boys," Bonn coach Michael Koch said. "We have been hit hard this season in terms of injuries.
"Especially at the power forward position today, Alex King got a bunch of work done. I think we won the game because we had key stops in the decisive stages. To win in Bremerhaven isn't easy, so again congratulations to my team."
Bonn open their EuroChallenge at KK Zagreb next week.
Zagreb are licking their wounds following an 84-64 defeat at Partizan Belgrade in the Adriatic League.
The game was tight until the last eight minutes when Partizan stormed to a convincing win.
They ended up outscoring Zagreb 23-10 in the last quarter.
Zagreb began the Adriatic League campaign well but have now lost three straight.
"We stopped (playing) in the 32nd minute," said Zagreb coach Denis Bajramovic.
"The difference in the end, it created a different picture compared to what we had built in the first three quarters.
"I apologize to the fans for the last eight minutes."
Zagreb center Mario Kasun had 18 points and Krunoslav Simon 14.
KK Krka are another EuroChallenge side in the Adriatic League only they are riding a three-game winning streak.
The club has beaten Zagreb, Nymburk and over the weekend, Red Star Belgrade.
Krka got a balanced scoring attack against Red Star with Smiljan Pavic and Bojan Krivec (3 steals) leading the way with 13 points apiece.
Zoran Dragic, the younger brother of Slovenia and Phoenix Suns guard Goran Dragic, had 12 points, eight rebounds and three steals.
Krka will play Zagreb, Bonn and BK Prostejov in EuroChallenge Group E.
Prostejov beat Novy Jicin 92-78 in their last game in the Mattoni NBL after getting 22 points from Andrius Slezas.
They are third in the league behind Decin and Pardubice.
Looking ahead to their first EuroChallenge game against Krka, Prostejov captain Jaroslav Prasil says the club must make use of its home-court advantage.
"This is a must win home game, especially," Prasil said.
"The fans will be our sixth player."