Kariobangi Sharks picked a 3-0 win in a Football Kenya Federation Premier League game at Kasarani Stadium to derail KCB's efforts of closing in on Tusker.
The Bankers needed the points to narrow the gap with the current leaders, Tusker but ended up going down to goals scored by Erick Kapaito, Boniface Onyango and James Mazembe.
Kapaito, who scored his 14th goal of the season, just needed two minutes to breach KCB's backline for the opener. Onyango, who opened his goal account with Kariobangi Sharks against the Bankers, added the second one in the 25th minute to hand a 2-0 lead to the Eastland club.