I've now heard two of the most successful American-based jiu-jitsu coaches - Lloyd Irvin and John Danaher - spell it out. Here's Danaher on Joe Rogan's podcast.
... my students could put opponents who trained much much longer than they had into a niche area which my students has so much knowledge of, so much training in that isolated niche domain, that they could take someone who had trained three, four times longer than themselves and have more knowledge in that one domain than their much more experienced opponent did.
