JDS didn't go full retard. He just couldn't deal with the pressure. I'd imagine it has to throw you completely off when the other guy is on your face from the very first second. Reem did it to Lesnar and Cain did it to JDS. A fight between these two isn't going to make the distance for sure.
The pace that Cain brought was unbelievable. He just imposes his will on the best of them. I just thought that JDS could handle that. This was out of left field for me with how Cain handled him. At the same time, I've always respected Cain's relentless pace, I just didn't think he'd tool JDS on the throughout the fight that much.
I watched that Carwin fight and saw how easily he shrugged off those takedown and clinch attempts. I just assumed he could do the same with Cain. I overrated his BJJ for sure. MISTAKE! Incredible neutralization of JDS's ground game.