I know hindsight is there, but I had thought I posted it yesterday - apparently it was sitting there in my memory tab, or wtf ever it is called when the site saves what were posting... BUT... Brawnagel losing to Sinclair was not a surprise, and I was eluding to not being surprised, even picking Sinclair (sorry... sue me).
That said, I believe they have rolled together a few times in the last year (national team camps) and Sinclair has some of the highest match IQ and after-match adjustments of any incoming frosh, ever... maybe even the actual highest. If he has wrestled with someone, even if not an actual match, I think he stands a very good chance to beat just about anybody - so far as there are no other serious gaps there (size, strength, skill, etc.), which Brawnagel does not have.