Joel Mogorosi struck twice for Phunya Sele Sele after Tumelo Tlou opened the scoring with an own goal at Free State Stadium.
Celtic went ahead in the third minute, as Tlou inadvertantly turned in a cross from the influential Mogorosi.
Mogorosi made it 2-0 in the 21st minute when he lifted his effort over onrushing goalkeeper Postnet Omony after latching onto a long-ball from the back from goalkeeper Bongani Mpandle.
Frank Mhango should have added a third goal early into the second period but the diminutive striker fluffed his effort from close range.
Mogorosi had the ball in the back of the net just before the hour-mark but his strike was ruled out for offside.
However, the Botswana international completed his brace in the final minute with a superb long-range shot.
Celtic: Mpandle, Fransman, Marubini, Rikhotso, Motshegwa, Letlabika, Mogogi, Lakay, Buchanan, Mhango, Mogorosi
Roses: Omony, Tjemolane, Khasipe, Tlou, Lubisi, Kgoadi, Phungulwa, Van Heerde, Matheba, Stevens, Majake