Hmm .. how about the Spurs concentrating their whole defense on Nash, and just decided to let Diaw beat them (last two games)? Nash is a great offensive player, and yes, he has to share some of the blame for losses, but the Spurs made it quite clear after Game 1 that they are not going to let Nash stop them. The strategy is to take the ball out of his hands as much as possible, and let players like Stoudemire and Diaw make decisions. Even with that in play, Nash played better than most could.
On defense however .....
On defense however .....