Murray had a pretty bad first half of the year this year. Besides the semis of the AO and the Miami final, he did hardly anything. Bad showing at IW, awful clay season. On the other hand, he did very well in the second half of the year. He has a perfect window of opportunity to take the #1 ranking, at least for a few weeks, in the first half of next year. If he can win either the AO or Wimbledon, he will have points for 2 slams as well as the Olympic gold. Combine that with better showings at the first few Masters and there is hardly any way he can't be #1.