Say what you will about MMA but that's close as you can get to actual, legal hand to hand combat. As in not choreographed comic book, movie TV action.
Americans tend to be successful at it, very successful. Not just white Americans. Black Americans. Latin Americans, etc.
There are successful Asian MMA fighters. However, it seems the issue they face is that they don't have access to the super camps and level of training that American MMA fighters can get.
The Americans that are successful, most of them have been training in amateur wrestling from grade school. So that athlete mentality has been drilled in them since childhood. Brazilians seem to be natural grapplers and excellent BJJ practitioners, not all but many.
There are good Asian fighters, but most of them tend to be specialists and aren't as well rounded as the super-camp fighters because they are training and drilling in multiple styles nonstop.
I guess its racist of MMA when clean cut American white surfer dude Luke Rockhold was able to elbow the hell out of Lyoto Machida, a Brazilian Japanese MMA fighter and former UFC champion. And then Luke Rockhold got the hell knocked out of him by Michael Bisping, a white British MMA fighter who started out primarily as a kickboxer.
Anyway a tangent here, but I'm just giving real-live combat examples. In real ****ing fights and combat there's none of this "but so and so should be Asian in order to be good at stuff!"