Admitting failures/ weakness

[Mammavoice]

My daughter is 13 and believes she is the best at everything?! When she fails at something or is obviously not good at it, she lies about it. She will lie about getting goals (soccer), baskets(basketball) , or just blame it on an unfair referee or aggressiveness of other players. She won’t admit that she didn’t play well.
The worst is she believes she is a good singer, when she’s terribly off key and can’t hear it? She believes she is good? We have been very supportive with everything, knowing she is lying as to not break her heart, I’ve offered singing lessons and she says she doesn’t need them because she’s already a great singer. (This may also stem from her jealousy of her sister who is a very talented singer) Anytime her sister wants to show us an audition piece she will jump infront and make us listen to her instead? 😣
Even her teacher at school has mentioned that she won’t admit when she doesn’t understand a subject at school. She won’t ask for help. She believes she knows all and is talented at everything? I’ve read posts where everyone says don’t tell your child they suck at something but I also believe she needs to admit to herself and to others when she can’t do something or doesn’t understand something. She needs to be able to deal with failures,...no?

Sounds like she might actually be very insecure (especially with a talented older sister) so is trying to compensate? Does she get genuine praise for what she is really good at?

We sure do praise her, all the time.
Sometimes overly praise her too. Even her older sister, hides her own accomplishments from us and doesn't flaunt or even pursue her own talents, ever, in-front of her sister as to not instigate a flare up of jealousy? It's like we walk on eggshells to have her not be jealous? She cannot and will not accept that anyone can better than her at anything? She is never happy for her older sister, only annoyed and jealous? The older sister always praises her and supports her and tells people about how talented her sister is, but it's never enough?

When I tell her that I am so proud of her, that she played amazing, and she's a very talented **player.... she says "I know, of course I am?"

This may have happened because you praised her for innate talent instead of praising for trying really hard or working really hard.

www.understood.org/en/friends-feelings/empowering-your-child/celebrating-successes/ways-praise-can-empower-kids-learning-issues

Thank you for your suggestions Surreygirl1987 and tigerquoll . I really appreciate anyone giving me something to think about.
Tigerquoll- I know exactly what you mean about the praise for innate abilities.
But at our house, it's quite the opposite? I explain to all my children that I would be more proud of them for getting a lower mark on an exam if they really studied hard for it and tried their best, than getting a higher mark without even studying. I only praise when there is effort involved.
So there goes that theory?
I'm just at my wits end? I explain to her that I am proud of her when she studies, when she tries her best and when she does things with good intentions. Practice makes perfect, although perfection is overrated, trying your best, being kind to others.... but how do you teach a child to be humble and accept weaknesses, or better yet admit that weakness and strive to be better?