This is a great challenge. To achieve this honour he would have to...
1) Clean up the non GS events by winning...
Dubai, IW, Miami, 1 Clay Masters, Halle, Motreal, Cincy, Shanghai,Stockholm, Basel, Paris & London...according to some tools this is a reasonable/realistic expectation
2) Reach the finals of the remaining slams...
3) Hope that
Murray wins AO,
Nadal loses at least one Clay Masters title and loses in the 1st round @ both Wimbledon where Roddick wins and USO where Djoko wins.
Djoko only wins 3 micky mouse events aside from the USO.
Nadal only wins RG and 2 Masters events and has an awful season.
I believe that should be enough to secure the coverted pushniaki number 1 spot
Let's be positive folks