Boniface Muchiri who has been in sensational form, helped the Brewers register a win after last tasting it on March 27 against Kariobangi Sharks.
After a first half that saw rare chances created by both sides, Muchiri, who has been on the scoresheet for the last three matches, headed Tusker in front in the 51st minute.
The Brewers won a corner after KCB’s goalkeeper tipped the ball over the bar when Timothy Otieno's goal-bound header almost caught him unaware due to the overcrowded penalty box.
He almost grabbed himself a brace in the 69th minute but his header went off target. Muchiri rose to meet a long throw from Rodgers Aloro who entered the pitch in place of Hillary Wandera as the second half resumed.
Chances for Otieno, and Jackson Macharia were wasted as Tusker eventually stamped their authority over the Bankers.
KCB have won only once against the Brewers and even the last meeting saw them leak three goals which were put into the net by Sydney Ochieng, Timothy Otieno, and Loyd Wahome.
The 1-0 win for KCB came in 2015 before they were relegated. A 1-1 draw has been recorded by the two sides twice in 2013 and in the repeated leg of the 2015 season.
Tusker XI: Robert Mboya, Eric Ambunya, Hillary Wandera, Justine Omary, Brian Odhiambo, David Naftali, Peter Nzuki, Boniface Muchiri, Noah Wafula, Jackson Macharia, Timothy Otieno.
Subs: Bryne Omondi, Rodgers Aloro, Kevin Wafula, Faraj Odeny, Mike Madoya, Clyde Senaji, David Majak.