Sipho Chaine, Teboho Khasipe, Lucky Baloyi, Victor Letsoalo, Motebang Sera and Harris Tchilimbou were six changes for Celtic, who looked to become the last Absa Premiership side in the last four.
Mbulelo Wagaba posed a few issues for the visiting side earlier on with a looping delivery from the right landing on top of the net following a shortly taken corner.
Celtic stayed on the back foot towards halftime, as Sporting through Wagaba and Decide Chauke had the visitors on their toes with a few tricky moves.
Sporting continued to dominate after halftime with Chauke heading narrowly over the top from Ricardo Versuur's low cross from the right.
All their work were undone after Sera ran to the byline to send in a low cross for Letsoalo, who tapped home to give Celtic the lead against the run of play ten minutes gone.
Siwelele had their tails up following the breakthrough and Mlungisi Maranti scrambled to the bottom corner to parry Siphelele Luthuli's free-kick a little later.
Celtic threw more pace and skill to their front line after 70 minutes with Tchilimbou making way for Andile Fikizolo.
Pressure however mounted and Sporting levelled after Letsoalo's header from a free-kick ricochet off Chico Muchanga and into the net with 12 minutes remaining
Sporting pushed for the winner in the final minutes as Celtic hanged on the edge, but extra time was the next destination.
Chaine, who gave away a penalty in the final minute of extra time after bringing down Katlego Mojalefa, recovered to spare Chauke's blushes from the spot.
Oscarine Masuluke replaced Maranti in goal for Sporting as penalties loomed, however the move didn't pay off as the former missed the decisive kick with Celtic winning the shootout.