Walk the line

This weekend Hannah had her 1st soccer game with this new Academy League she's playing on. She has been playing soccer since she was 5 so this is going on her 3rd year and she has played every season. It's wonderful to see the skills she has acquired and also the knowledge and understanding of the game. She's a pretty smart girl and she claims she really loves playing. But she can be a bit of a thinker and I'm wondering if that interferes with her being able to just instinctively play. I am not quite sure how to go about motivating her to be the best she can and to give her 100% in all that she does. I find my self watching her play and getting frustrated because it seems to me that she is not giving her best. I think she can do better. After her game she asked me if I thought she played well. I did not want to lie and say,"Oh yes Honey you played so well" when I really think she did not. And on the flip side I did not want to crush her little spirit and say, " well I really don't think you gave it your best". I don't know how to let her know I think she could be trying harder with our her getting discouraged especially if she feels like she gave it her all. There's playing well and there's playing your best. In the past if I have ever tried to give her some constructive criticism she gets extremely defensive and whines that I don't think she is good enough. If I ever suggest that she needs to be practicing more she gets upset and says I am suggesting that she does not know how to play and she already knows how to play so why should she practice. She thinks she knows it all and she thinks she is good enough already when in reality it isn't quite so. To be really good at something it takes practice and more practice and I can't seem to make her understand that with out her getting extremely upset. So I'm wondering if I should just spend some time telling her that she is playing really well ( even if she isn't) just to build up her confidence and hope that from that confidence her improvement will be manifest. Or would that backfire and actually cause her to have this false confidence and therefor believe even more that she does not need to improve. I don't know. Everything with Hannah is always a lot of work and a lot of mental exhaustion. There is this extremely fine line that has to be tiptoed on when dealing with her and if you tiptoe ever so slightly on the wrong side of that fine line it results in some major drama and melt downs. I try very hard to avoid drama and melt downs.....I don't do well with those. I just want to be a good encourager to her and help her live up to her potential because she has a lot of it. I don't expect perfection( well maybe I do a little) but I expect her to give 100%. Is that wrong?