Zabaleta struck from close range after 85 minutes as City, who had been dominant in the early stages, finally wore their resilient hosts down.
Platt said: "When you have got players of the ilk we have got - the Yayas, Silvas, Agueros, Tevezes - they all work hard and do what they have to do, but you need to sprinkle into that mix those players that often go under the radar.
"What is pleasing is that he scores a goal in a cup match and he can get some headlines, but he won't be bothered about that.
"He isn't bothered about headlines. Those kind of players aren't. It's not what they play for. He is an eight out of 10 man every week. For professionals he is just a top man really."
Platt added that Zabaleta's latest strike was no fluke.
He said: "We get players into advanced areas. It is not by luck Zaba gets into those positions.
"The way we play we get a lot of players forward. Zaba has been in those positions many times and he tucked it away nicely."