Kenyan champions, Gor Mahia, suffered a shock 2-1 defeat at the hands of struggling Western Stima at Thika Stadium on Saturday.
Rogers Ouma fired the visitors ahead barely four minutes into play before Michael Karamor extended the lead in the 60th minute from the spot after skipper Harun Shakava sent his counterpart Baron Oketch tumbling in the area.
Gor pulled one back in the dying minutes of the match through Geoffrey Ochieng after the right-back came on the end of Clifton Miheso's cross, the effort coming too late in the day.
At Utalii grounds, AFC Leopards fought back from a goal down to edge Wazito 2-1.
Michael Owino put Wazito ahead in the 35th minute but Bienvenue Shaka canceled the deficit in the 56th minute before Elvis Rupia's late strike from the spot separated the sides at full-time.
In Nakuru, Kakamega Homeboyz denied KCB a chance to topple leaders Tusker after the sides settled for a barren draw in a drab affair devoid of any sparks.
Elsewhere, Mathare United's dream for a second consecutive win was nipped in the bud by Posta Rangers who beat them 2-1 at Ruaraka Grounds.
Jackson Dwang' latched onto Francis Nambute's neat-through pass to fire the mailmen ahead in the 10th minute. Then Dennis Oalo forced Austine Ochieng into a howler as the defender turned the ball into his own net to double Posta's advantage in the 38th minute.
It was a baptism of fire for the defender who had just replaced namesake Kennedy Ochieng following an injury in the 29th minute.
The results leave KCB in second place with 43 points, one adrift of leaders Tusker as AFC Leopards ascend to third with 40 points. Gor have now slumped to fourth still with 38 points.
