Japhta has been one of the best finds this season with Stars and his performances have been rewarded with a national team call-up for the friendly against Brazil this weekend.
Japhta was the hero for Ea Lla Koto recently when he scored a brace during the Free State Derby win over Bloemfontein Celtic.
“He is a raw talent,” Carnell tells KickOff.com.
“He lacks a few tactical aspects of the game, but we are working on it. He is coming on well and it is good to see that he has been rewarded with the Under-23 call-up.
“He is still on a learning curve and I hope the Under-23 coach [Owen da Gama] will be patient with him because he has such great potential.”
The Under-23s touched down in Brazil last night ahead of their friendly against the Olympic host nation on Sunday.