Tuyisenge and Juma score in each half as K’Ogalo take first leg advantage.
Gor Mahia have one foot into the group stages of the Confederations Cup after registering a 2-1 win against New Stars of Cameroon at Kasarani on Sunday.
Jacques Tuyisenge and Lawrence Juma scored a goal in each half for K'Ogalo's vital victory.
Without suspended duo of Haron Shakava and Joash Onyango, Gor Mahia coach Hassan Oktay opted for Charles Momanyi and Joachim Oluoch at the heart of his backline.
The two held on quite well in the entire first half though they remained largely untested by the visiting New Stars.
Gor Mahia were quick off the ball at the first whistle and repeatedly knocked at the New Stars' backline in search of a goal.
Lawrence Juma's long shot in the sixth minute whizzed past Patrick Kibyen in goal.
Three minutes later, Francis Mustapha hit the post while trying to convert Boniface Omondi's cross.
In the 29th minute, Boniface Omondi was denied by the New Stars goalkeeper.
By the half hour mark, it was clear that Gor Mahia were lacking a scorer given the number of chances they had created. Tuyisenge remained lost for most of the half.
The visitors could have grabbed the lead in the 31st minute as a harmless shot from Gildas Richard was nearly swayed by the wind into Gor Mahia's net with goalkeeper Boniface Oluoch beaten.
A free-kick in the 35th minute was curved well by Nelson Joel in only the second attempt at goal by the visitors.
It was, however, Gor Mahia who ended the first half ahead with Juma completing a Shafique Batambuze pass.
Inspired by the first half goal, the home team came back strongly in search of a second.
It was Juma who was denied by New Stars goalkeeper in the 47th minute from a well taken long range shot
New Stars made the first change with Roddy Junior replacing Camille Kuoyekimina.
The visitors also rested Roland Lakem for Benjamin Bichem. The two changes did not have any immediate impact as Gor continued to dominate.
New Stars defender Orian Jores got the first caution of the match when he fouled Mustapha at the edge of the box.
The return match will be played on January 20.