McCarthy praised the physically imposing Mthembu, who was recruited from Free State Stars, for his ability to play with his back to goal and provide an outlet for the Citizens' attack.
The ex-Orlando Pirates and Kaizer Chiefs targetman has already got off the mark for the coastal outfit, netting in a 2-1 league loss at Baroka on August 8.
However, Mthembu is a doubt for Saturday's visit of Golden Arrows after being forced off the park in a 1-0 MTN8 win over Maritzburg United last weekend following a brutal challenge from Rushine de Reuck.
"My main man. Shaka Zulu is the man," McCarthy said.
"He gives us a completely different outlook for the way we play. If you looked at us last season we were a good playing team but we didn't have bite. We didn't have that instinct, we didn't have someone, that striker that gives us the depth and is able to hold it up when we have our backs against the ropes.
"He has come and given us that outlet, so we are a completely different side now. Now we can fight, we can protect it [the ball] and then we can play under pressure as well.
"Because we've got a striker that gives us that outlet and you know [that] Zlatan Ibrahimovic aura. So I'm very happy to have Shaka," concluded Bafana Bafana's all-time leading marksman with 31 goals.