Del Potro is a scary foe who can burn very brightly for periods as was experienced by Roger in the 2009 US Open final, but even this year against Djokovic and Nadal in RG and Wimbledon respectively. His shit wrist injury held him back for a long time and he's long overdue a real run of form now and a revisit to the top 5, in my opinion. In fact, he might have a chance for a Major next year for realz.
Like all ballbashers, he will have a hot streak, and then play crap for the rest of the year. Book it.
He looked good against Nadal, on the baseline, but Nadal isn't 100% or even close to it.
I wouldn't be surprised if he made a slam final though, but I would put money that he won't be ranked above #5 - Nadal was just being overly courtagious
because he won the match.