Tuesday's triumph avenged their 78-55 defeat at Bonn on November 26 and improved Keravnos' record to 1-3 while dropping Telekom Baskets to 2-2.
Keravnos seized the initiative late in the first quarter.
Bradley Buckman's lay-up with 2:17 to go in the opening frame tied the contest at 16-16 and Barisa Krasic followed with a three-pointer.
Krasic then split a pair of free throws before Patrick Flomo's lay-up made cut the lead to 20-18 with 10 minutes played.
LaMarr Greer scored on a drive and Buckman followed with a lay-up and three-point play and another lay-up for a 29-18 Keravnos advantage.
The lead grew to 38-23 inside the final minute of the quarter after a Greer three-pointer.
Telekom Baskets went to half-time behind 55-40 and Keravnos effectively delivered the knockout by scoring the first six points of the third quarter.
Panagiotis Trisokkas scored 16 points, Krasic 15, Greer 13 and Buckman 11 for Keravnos.
For the German outfit, Ken Johnson scored a game-high 21 points.
Keravnos were 17 of 25 at the line compared to Bonn's 10 of 12.
Michael Koch - Telekom Baskets coach:
"Congratulations to Keravnos. They deserved to win this game. We had a problem to find our offensive rhythm. The fact that we only scored 25 points in the first half says it all. In the second half we tried to come back into the game but it was very difficult as Keravnos played hard and better over the 40 minutes. This loss will not cost us too much. We travel next to France with a 10 point lead and our only objective to win that game, even by one point. I think we still have a good chance."
Ken Johnson - Telekom Baskets player:
"We did not have a solid rhythm tonight. Keravnos was aggressive and played smarter and deserved to win."
Vasilis Fragias - Keravnos Nicosia coach:
"Congratulations to my players. Tonight they played very tough and smart. After the weekend's loss in the Cyprus League the team was down and as few people expected us to do anything tonight, the team played without stress. Our main focus is the Cyprus league. Our chances to qualify to the next round of the EuroChallenge are very slim, but we will go to France and fight it out."
Panayiotis Yiannas - Keravnos Nicosia player:
"I want to congratulate my teammates. We had lost four out our last five games and our psychology was not the best coming into this game. Tonight we played hard and very smart and showed everyone that we can beat opponents such as Telecom which is top of the German League. This win will help us a lot especially our psychology in the Cyprus league."