The key for Roger is winning today's final. If he does it's difficult to see how Djokovic could hit back until Federer has to start defending his indoor titles.
yes but the funny side is that if Fed wins today and if Djokovic does the same result as Fed in the Olympics, and assuming it's at least a quarterfinal, Djokovic would take the number 1 back ... at least for one week
... because Fed would replace a 90 points result, Djokovic not, and Fed would only be 75 points ahead.
Next months have the potential for a succession of changing number 1s anyway.