I'm not sure that GSP is the underdog in this case. Silva has had several impressive victories but really he's just become a fan favorite by knocking out lower-tier guys stylishly, while St. Pierre has shown time and again that he really understands the psychology of a fight and is probably the most well-rounded MMA fighter in the world. Not to take anything away from Silva, but it seems like he's one of the only big stars UFC has produced whose fights haven't gotten harder as he progresses. He started with Rich Franklin basically and made his way to guys like James Irvin and Patrick Cote, while St. Pierre began dominating nobodies like Justin Bruckmann and has since beaten the likes of Karo Parisyan, Matt Hughes, Frank Trigg, Sean Sherk, BJ Penn, etc., sometimes more than once. He outwrestled Josh Koscheck, who had been tauted "the greatest pure wrestler in the UFC." He made Matt Serra's victory look like the fluke it was. Silva has been in bad situations before, but nobody has yet been able to make him pay for it. St. Pierre is really good at making people regret things like that. Gotta give the edge to St. Pierre.
