Im still amazed that people are calling the punch JDS landed a 'lucky shot'. He has hit most of the people he's fought with blistering heavy shots and the vast majority of them have gone down. Off the top of my Head I can only think of Nelson and Carwin who have managed to stay concious after eating a big shot from JDS.
Im not saying it is impossible, but I'd be very surprised if Cain can take one of those shots again from JDS and not go out. I'd also be surprised if It goes past the 2nd round.
If Cain cannot take JDS down and implement hos GNP, he'll get deja vu and become desperate. As you said, it's been shown JDS can knock him down as he normally does, with the exception of Carwin or Nelson.