From a Chris Douglas-Roberts interview with Andrew Katz in the current Dime Magazine:
There's a rumor that you've never lost a game of one-on-one in your entire life. True?
That is true. DK [Derek Kellogg] knows I've never lost one. I've never lost one though. You could ask around from my being in Detroit, or any of my teammates, we played a lot of one-on-one. A lot of the guys were close. Derrick [Rose], Robert [Dozier], a lot of them were close. But I've never lost one. Ever.
Soon he'll have half the NBA lining up to break the streak, and somebody will get him. A streak that like that is just unbelievable.
And if nobody does break the streak in his first few months in the league, somebody should probably make a TV game show where contestants come from all over the world trying to beat this guy, week after week.
Here's a Douglas-Roberts video scouting package from Jay Bilas: