Agreed. I'm not sure you can compare the two matches.
Montreal, was Petra's first match, changing over from the grass season (including the Olympics). Thus several of the top 10 players who traveled to Canada had sloppy first and second rd matches due to the change of surface, environment and fatigue.
Pervak, like what happened with some of the other players, caught Petra when she was acclimating her body to the fatigue, NA conditions and court surface, and still lost.
Wozniaki's game on the other hand, is less susceptible to break in on a hard court, unless her fitness is suspect, due to the defensive nature of it. Plus, I'm sure Wozniaki's been practicing on hard courts (if she's been practicing at all and not with Rory visiting Australian sights).
Despite the errors (60 UE): Pervak did play a good match. There were many times she had the lead and lost the lead, but she always stayed aggressive, dug down and managed to come back back. She just wore Caro down. It wasn't all Woz's fault.
Pervak's coach was good as well. We'll leave Caro's coach, 'well enough alone'.