Andy, like Tim Henman suffers at the hands of the media from the misconception that he's a dour faced cunt. Having read parts of Murray's book it's not the case. But Tim didn't go out of his way to try and "prove" that he wasn't boring because he didn't care and Andy's the same. It's ridiculous to label him "moody". He's just competitive.
There's a difference between being arrogant and confident. To be honest he doesn't strike me as either of those. He knows his limitations. He knows who he should be beating and who he's maybe not capable of beating yet.
Rafa Nadal was the only player in the top 10 that Murray hadn't beaten. Now there's not a top player who he hasn't beaten. There's no reason why he can't win tonight.