I don't think this will affect Nole one jot (assuming he wins). All of the top guys (apart from Federer apparently *cough* Olympics 'tired') are capable of playing five hour marathons then returning two days later and doing it again. Djokovic's match against Nadal is testament to that.
Wouldn't surprise me one bit to see Djokovic win this, then trounce Berdych and Ferrer in straights.
Mentally, he will be in top form if he wins this. That's the bugger!