Assuming this is his first use of it against Jiren, I'd still say Goku wins. Kefla has the advantage in power, but the gap between all 3 uses of UIO is implied to be pretty small and Galu can get the opening he needs with superior reactions if this is a ToP match.
If it's a regular win by KO fight though, Kefla likely wins due to outlasting Goku's limited stamina.