Murray's loss and its significance

To carry on with the theme of upsets at this US Open on the Mens side, the defending champion Andy Murray lost his quarter final match in straight sets to the inspired Stanislas Wawrinka a few days ago.

Wawrinka has been the surprise package of this tournament, reaching the semi finals of a Grand Slam for the first time. He beat 5th seed Berdych in 4 sets in the 4th round, then Murray in 3 sets before narrowly losing last night in a stunning 5 set match against Djokovic.

For me, the quarter final between Murray and Wawrinka was an incredible match and I could not believe my eyes at time.
I could not believe how well Wawrinka played and that he was the same Wawrinka I and the rest of the tennis world knew. Not only did he play some amazing shots and paint the lines, what stuck me was how many winners he was able to conjure and when he wasn't hitting winners, how he was able to dictate the play. Wawrinka was able to dictate play with both ground strokes and especially on Murray's second serve, which has been a weak link of Murray's game for a while.

I was also surprised by how out of sorts Murray looked. Although Murray played below par, Wawrinka played such a good match that the odds are Wawrinka still would have won if Murray played well, but not so comfortably by 3 sets. Murray failed to find the aggressive play that has been so integral to his recent improvements in his game. Concerning that match itself, despite underperforming, I think Murray won't be too disappointed as he knows Wawrinka played out of his skin.

However, the impacts the loss has will be more disappointing. It slams to a halt Murray's pursuit of the number ranking, with the loss meaning Murray will relinquishing 1640 ranking points, putting him even further behind Nadal and Djokovic. It also raises questions about his ability to defend his titles. How will he fair defending his wimbledon title after he failed to find form when defending a grand slam for the first time this US Open? One interesting thing is that Nadal said he found it very difficult to motivate himself after winning his first grand slam, the 2005 french open, and subsequently lost in the 2nd round of wimbledon to Muller. Maybe it was just a case of Murray understandbly failing to motivate himself?

Thoughts?