Looks like R.J. Hampton made the right decision passing up college basketball to get a check in Australia ... 'cause he's already dominating pro basketball players, according to NBA skills trainer Tyler Relph.

Relph is a basketball guru, having trained guys like Julius Randle, George Hill, Marcus Smart and Amare Stoudemire. He's currently working with Hampton before he heads overseas.

How's he getting him ready? Throwing him into the DEEP water with European pros and seeing what he can do, and according to Tyler, he can do a hell of a lot.

"95 percent of the time he's the best player on the floor," Relph says ... "Athletically the things that he can do, the spots he can get to."

Relph says Hampton ain't quite Kobe yet -- he says the kid is still young and has some things to work on, some of which are actually out of his control.