The KZN club had gone into the match on the back of a 2-0 win over SuperSport United and looked confident early on as Camaldine Abraw set up Ovidy Karuru a minute into the game, but he fired wide.
Former Kaizer Chiefs man Abraw then headed wide in the 19th minute, Celtic’s first chance coming soon after when Deon Hotto was denied at point-blank range by home keeper Siyabonga Mbatha.
Karuru also seemed to have a good appeal for a penalty turned down after he appeared to have been taken down by Ronald Pfumbidzai in the box.
But although Usuthu ended the first stanza stronger, Phunya Sele Sele came out and took command of the match after the break.
But both Hotto and defender Tshepo Rikhotso squandered opportunities before Mbatha made a stunning save to keep out a well-struck effort from Vusi Sikhweni from outside the box.
AmaZulu managed to regain a hold on proceedings as the game entered the final quarter, but were unable to unlock a stubborn Celtic defence as the Free State side managed to avoid a third successive defeat. The result leaves Celtic in ninth position while Usuthu are 13th.
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