KCB ended the Eldoret-based GFE105 unbeaten run in the National Super League.
GFE had won four consecutive matches since the start of the league however they were overpowered at home, Wednesday.
Louis Osman put the visitors ahead in the fourth minute after heading in a foul shot from Dennis Ng'ang'a just outside the 18m-box beating GFE's goalkeeper Samwel Kamunya.
The home team then mounted pressure on their opponents but Chrispinus Onyango of KCB missed a point blank shot saved by Kamunya.
The breather ended 1-0 and on resumption, both teams were equal to the task creating many scoring opportunities however wasting them.
GFE was awarded a penalty in the 55 minute after Bethuel Wambo badly tackled Ayub Asila but Onyango failed to score as the score ended 1-0.
The win earned KCB four points to rank top ten with 7 points but GFE is still leading with 12 points.
Joshua Obare coaching GFE said they had realised their mistakes and they would be keen on the next matches.
“Our opponents were tall but my side also failed to take instructions.They played high balls,” Obare said.
KCB's Leornard Saleh said they are keen on doing well in the league in order to get back their promotion to the top flight league.