A poor defensive display resulted in Cecil Lolo turning the ball into his own net within the opening 11 minutes of the game, while a second was added by Carlinton Nyadombo in the second half.
Nathan Paulse bagged a consolation in the 90th minute, but it was AmaZulu’s win for the taking.
Franklin Cale was the first to have a crack at goal with his fourth minute drive from range, but it sailed narrowly over.
AmaZulu were gifted a goal when Lolo spectacularly turned the ball into the back of his own net with a diving header, after Aiden Jenniker failed to clear the ball efficiently.
The Urban Warriors pushed for an equaliser, and on 20 minutes Toriq Losper tested Tapuwa Kapini from 15 yards out, but it was easy pickings for the goalkeeper.
Two minutes later, Ayanda Dlamini’s ball went through the legs of Dominic Iaacs following another scrappy moment in the Ajax defence, but Sean Roberts cleaned up.
Ajax were dealt a blow just before the half hour mark when Losper had to be replaced by Keagan Dollie due to injury.
Usuthu had a penalty appeal waved away after Thulani Hlwatshwayo brought down Bongani Ndulula on the edge of the area six minutes before the break.
Ajax fell 2-0 behind afer the restart, after some more scrappy defending from Nkosinathi Mthiyane’s corner-kick.
The Urban Warriors’ defence was left at sixes and sevens and the ball fell to Nyadombo at the far post to tap in.
Usuthu continued to pile on the pressure and their attacks often left Ajax’s backline worse for wear.
Paulse made it 2-1 with a diving header at the stroke of full time, but it was too little too late for the hosts.