Ayanda Dlamini fired Usuthu ahead early in the first half but Craig Rosslee’s men were denied maximum points late in the second half when Carlington Nyadombo deflected the ball into his own net.
In the fifth minute Njabulo Manqana picked out Dlamini with a cross, and he sent his header past Daniel Agyei for his second goal of the season.
Chances were few and far between at Goble Park. Paulus Masehe tested Aubrey Mathibe just after the half-hour mark, and Danny Venter sent a free-kick over the crossbar just before the break.
Mathibe was called into action again in the second half, blocking an effort from Sadat Ouro-Akoriko in the 69th minute, before making a diving stop to deny Camaldine Abraw three minutes later.
However, Usuthu were dealt a blow in the 79th minute when Nyadombo nodded past his own goalkeeper while trying to make a clearance.
Rosslee’s men pushed on for the winner, and Goodman Dlamini shot just wide with three minutes remaining, before Nkosinathi Mthiyane also sent an effort wide of the upright in added time.
AmaZulu remain in seventh place with 14 points from 11 matches, while Stars have moved up to ninth place with 12 points.