It wasn't a case of DC being bad, but Silva just being that damn good. There's always the chance that you're seconds from being KO/TKO'd by him and that plays a huge part in what you can and can't do while fighting. We've seen it in so many Silva fights where he's just toying around with the other guy and then turns on a switch and ends the fight in 10 seconds because he's finally had enough of the other guy's shit
I don't think that you can really "figure out" USADA testing, because it is completely random and at all times. I think DJ was tested like 4 times within 2 weeks or something leading up to his previous fight. He was on a Twitch stream playing video games when they showed up out of the blue and he had to cut the stream short so he could piss in a cup hahaha