It affects people differently though. You see some players on court after long flights to different timezones and they look fine, while others struggle to adapt to the time difference. I think Andy often seems to struggle initially, but as he's got a few days until his first match hopefully he should be ok.
Katie, I fall apart a bit when the clocks change, especially when they go forward! But your post is absolutely right, and Andy himself has said that he doesn't cope too easily with jet-lag. Djokovic on the other hand never seems to be affected and Federer and Nadal too seem to cope well.