I think this was a very stupid match up to give Mir for his return to the Octagon; and obviously he was given this match up because they thought Pe De Pano, with only one other MMA match in his career, would be an easy match up. The first problem being that Mir's specialty is submission, and while he has been impressive in the UFC, in terms of pure grappling skill he is not even in the same category. Second problem was evident at the weigh in; at 257 pounds Mir was going to gas quickly, where as at 233 Pe de Pano was in better shape than most of BJJ and Submission Grappling wins. I am not sure if the leg played a factor in Mir's loss as much as the mat rust. Once it hit the ground it was all Pe de Pano; he may be submittable, but the "Hail Mary" submissions that Mir can get against lesser grapplers were clearly not going to work here.
One thing that really surprised me was talking to a number of hard core jiu jitsu enthusiasts, many of whom have not cared for Pe de Pano's actions in the past, and they were decidedly very happy that he won, and moreover that Frank Mir lost. I think if Pe de Pano continues to show the level of dedication he obviously has for MMA and look to become well rounded, and minds his manners, than he can actually win over American fans who were rooting against him before.