As you all know i am a huge roger federer fan. That being said i saw some big forehands from del potro. Ive never seen roger play that far by the baseline. Its simply a matter of del potro hitting it harder and flatter. I feel that roger played with a little too much topspin that match and simply did not hit it as hard as he can. It was simply that del potro pushed federer back vertically not horizontally. Del potro forced federer to make errors by hitting it long, but thats what happens when you hit it deeper. Credit to del potro--he outhit federer.