Cape Town - Bloemfontein Celtic dropped out of the top eight after AmaZulu scored a late equaliser to clinch a 1-1 draw at the Dr. Petrus Molemela Stadium on Sunday.
The visitors made a bright start, but Siwelele absorbed the early pressure without any real scares.
Usuthu's best chance arrived in the 26th minute as Cele directed a header just wide of the target, before Celtic created two openings in quick succession.
However, Deon Hotto steered a free header straight at Siyabonga Mbatha on 31 minutes and the visiting keeper was called into action again moments later to parry away a long-range effort from Kabelo Dlamini.
Butholezwe Ncube threatened to break the deadlock six minutes into the second half with a curling free-kick that drew a superb save out of Patrick Tignyemb, who was at his best again to deny Thembela Sikhakhane on 63 minutes.
Those saves proved crucial as Phunya Sele Sele made the breakthrough on 82 minutes. There was little Mbatha could do as Jacky Motshegwa's drilled effort from outside the box on the left speared into the bottom-right corner of the net.
But Mhlengi Cele rescued Celtic with an 86th-minute equaliser and it was a clinical finish from the forward, who fired past Tignyemb from a tight angle to earn a share of the spoils for Cavin Johnson's men.