Oliech scored in either half in between Kenneth Muguna’s opener and, Nicholas Kipkirui's third goal. Oliech, however, missed a chance to grab his first hat trick for the Kenyan champions when he blasted his effort from the penalty spot.
Muguna broke the ice with a perfectly taken free-kick, then set up Oliech for K’Ogalo's second goal with just 20 minutes gone.
A slippery pitch at the Green Stadium saw Zoo miss a chance to cut Gor Mahia’s lead after keeper Shaban Odhoji denied Dennis Chetambe from the spot.
Kipkirui, who started from the bench, came on in the second half and the striker, rounded off his former teammate at Zoo Kericho for K’Ogalo’s third goal of the day.
Undone with the business at the Green Stadium, Kipkirui set up Oliech for the fourth goal to help K’Ogalo pick a fourth straight win over the Kericho-based side.
Zoo Kericho starting XI: Elungat Martin, Stanlaus Akiya, Kelvin Odour, Dennis Kawanga, Japheth Amakanji, Geoffrey Gichana, Dennis Chetambe, Kepha Ondati, Newton Ondari, Bernard Odhiambo and Kevin Omondi.
Subs: Brian Lumumba, Demonde Selenga, Ivan Mugisha, Ernest Kipkoech and Sabiri Sindani.
Gor Mahia XI: Shaban Odhoji, Wellington Ochieng, Joachim Oluoch, Geoffrey Ochieng, Charles Momanyi, Cercidy Okeyo, Samuel Onyango, Kenneth Muguna, George Odhiambo, Dennis Oliech and Erissa Ssekisambu.
Subs: Peter Odhiambo, Shafik Batumbuze, Pascal Ogweno, Boniface Omondi, Erick Ombija, Lawrence Juma and Nicholas Kipkirui.