Upper Hill beat Menengai High 19-9 to finish top of pool B of the Brookside games that are ongoing in Embu County.
The closely contested clash was to determine who finishes top and how the semifinals will be paired as both teams tried to evade defending champions Kakamega High.
Upper will now play St.Mary's Yala who finished second in pool A as Menengai takes on Kakamega High.
The first game, between Kakamega and Menengai, will kick off at 10am on Friday. Kangaru School, Miathene, Alliance and Galana have bowed out of the nationals.
Upper took early lead through Solomon Maleo's unconverted tries before Menengai hit back with three back to back penalties to lead 9-5 with 29 minutes to go.
The Nairobi champions would start the comeback starting with Calvin Kaindi's try that was converted by Abutwalib Wesonga. Emmanuel Kaiungu eventually scored Upper Hill's try that sealed the win.