Roy Nelson is back in action this Saturday at UFC Fight Night Brasilia against Antonio 'Bigfoot' Silva, but he's still thinking about his loss to Derrick Lewis back in July.

Speaking on the UFC Unfiltered podcast this week, Nelson said that referee John McCarthy's interventions had a lot to do with how his fight with Lewis played out and that discussions had taken place between the two of them both before and during the fight.

"The thing is, even in my last fight [Derrick Lewis], I even had a long talk with John McCarthy in the back and I said, 'Don't break us up when I'm working blah, blah, blah,'" Nelson said. "He was like, 'As long as you're doing damage that's cool.'

"When I had [Lewis] up against the fence, I was sitting there punching him in the legs and giving him a good old slog and all that, but then me and John McCarthy were having a conversation and he was saying, 'You gotta move' and I was like 'I'm doing damage.' I was sitting there having a conversation with him and I was like, 'Dude you're such a retard.'"

Nelson then continued by detailing the extent to which his conversation with McCarthy went into on the night inside the Octagon. Suffice to say, he was none too pleased with McCarthy getting involved so much in the action, and he didn't understand the referee's decision-making process.

"In that conversation, John goes, 'If you're in guard and you go body-body-head, body-body-head, I'm going to have to stand you up. But, if you're the guy on the bottom and you're just holding, I'm not going to stand you up to basically reward you,'" Nelson said. "I was then like, 'What if I'm in guard and I'm going body-body-head, but the guy is holding me just doing nothing? Who gets up? Who are you going to reward?' I was just dumbfounded. He didn't say anything and just told me to shut up."

The former The Ultimate Fighter winner then said that he thinks referees should only intervene in the instance of a foul, and that outside of those rare instances, referees should just let the fight take place naturally.

"I hate the third guy in there," Nelson said. "Just stop the illegal stuff. Don't let him poke me in the eye or hit me in my balls. Apart from that, I don't give a s*it. I don't think they jump in. I just don't think they know what the f*ck is going on.

"I think there is definitely a problem. I think the rules should be pretty simple -- just stay the hell out of it. It's a fight. If a guy can't get off his back, then he sucks. He shouldn't be in MMA -- he should be in boxing."