Another thing to note is that Pennington mentioned somewhere that she "broke her hand" during the Duke fight. This brings up some more points:
Is she exaggerating her story?
Wouldn't they have doctors check them before each fight to make sure they're in shape to fight? How would she have gotten cleared?
Pretty much everyone looked battered in the confessionals.
I do think Pennington will use her boxing to take Jessica down and submit her. Pennington can turn up her intensity when she needs to. Jessica is still a bit green on the ground and was in several bad positions during her fight with Roxy. With a little more explosiveness in the submissions Jessica would've been out.