Eduardo Ferreira, Franklin Cale and Sifiso Vilakazi scored for the hosts.
The Urban Warriors made their intentions clear from the start, creating their first chance in the seventh minute when winger Franklyn Cale put in a good low cross from the left flank, but Usuthu skipper Belux Kasongo put the ball over his own crossbar from inside the six-yard area, with Ajax striker Nathan Paulse in close attendance.
However, the hosts went ahead from the resulting corner when Eduardo Ferreira rose highest to head home Cale’s corner.
Vilakazi went close to extending Ajax Cape Town’s lead in the 15th minute when he was put clear by strike partner Paulse, but the former Free State Stars man sent his effort into the side-netting.
The visitors rarely threatened Hans Vonk’s goal and found themselves 2-0 down in the 32nd minute, albeit under dubious circumstances, when the Usuthu defence failed to clear a low pass by Nazeer Allie, who appeared to have handled the ball twice in the build-up, for Cale to score with a low shot.
The score remained 2-0 at half-time.
Craig Rosslee’s side continued their dominance in the second half and threatened just two minutes after the restart when Clifford Ngobeni latched onto a poor clearance by Belux Kasongo, but the midfielder’s shot from the edge of the area flew straight at AmaZulu keeper Kalililo Kakonje, who punched the ball clear.
However, the Urban Warriors were not to be denied and went 3-0 up in the 53rd minute when Vilakazi scored at the far post following a superb cross by Mkhanyiseli Siwahla.
Vilakazi wasted a glorious chance a minute later when he latched onto a header by Ferreira, but the striker put his effort over the bar from inside the six-yard area.
AmaZulu launched a rare attack in the 63rd minute, but Bulelani Matross sent his effort from a tight angle high over the bar.
Nathan Paulse should have made it 4-0 in the 69th minute when he was put clear on goal by Siwahla, and although Kakonje could only parry the lanky striker’s initial effort, the Usuthu keeper reacted fast to deny Paulse a second time.
Cale went close in the 85th minute hitting the crossbar with a right-footed volley, as the hosts continued to pile on the pressure. In the end Ajax Cape Town cruised to a comfortable win, moving two points clear of title rivals Supersport United, who meet Moroka Swallows at the Super Stadium on Saturday.