Two sides on the back of contrasting fortunes, the other yet to concede and chasing down the league leaders Bidvest Wits while the other experienced a midweek loss to the self-same Students.
Celtic were looking for an early penalty when Tshegofatso Mabasa was held back in the box, but the appeal was waved away.
The Free Staters made no mistake later on as Bongani Sam capitalised on poor defending and sent bicycle-kick into the back of the net from a corner.
Bucs had the perfect chance to grab a quick equaliser, but Thamsanqa Gabuza failed to profit from close range after a nicely played through ball.
Bucs were quite short of options to get behind the Siwelele defence whose rock solid pairing centre-back pairing marshalled by Lorenzo Gordinho stood firm.
Siwelele though were quick to maintain their solid positioning and Tebogo Potsane made quite a few forays on the edge of the box but nothing concrete troubled Bucs.
A shot from Mpho Makola outside the box couldn’t hit the back of the net, as it sailed over the top instead from close range.
Celtic managed to sustain an early onslaught from the visitors, who pressed for the equaliser after heading into the break trailing.
Early shots from Makola and Pule amongst others proved to be no harm to Patrick Tignyemb and his defence that has yet to concede.
The closest Bucs came to a goal in the opening spell in the second half found Ben Motshwari on the edge of the box and took a shot that sailed over the top.
A beautiful cross out wide from Pule found Gabuza, but the bulky forward failed to connect missing the chance completely to the dismay of Bucs supporters.
The goal continued to elude a certain Gabuza after failing to convert a chance at the far post following a cross in the box.
Disheartening as it seemed to Bucs, the pressure did not lower their mood and Happy Jele came close to finding the net but a goal-line clearance prohibited him.