Well... I suffered a lot that final, I think Fed played a little better and had reaaaally bad luck on some calls, but oh well, we shouldn't dismiss Delpo, he played really well.
Federer did not play better than Delpo. In fact, Del Po was never in danger of losing that match, Federer was and he did lose. Federer played a few points better and that's all there was to it. Del Potro was always in control of that match.