Bié chībùdàopútáoshuōpútáosuān le, chéngrèn rénjiā bǐ nǐ qiáng ba.
Stop with the sour grapes and just admit they're better than you.
Tips
culture
Direct calque of Aesop's 'The Fox and the Grapes' (狐狸与葡萄). The fable was translated into Chinese by Jesuit missionaries in the late Ming and entered colloquial use, making this proverb a rare clear-cut Western import.
usage
Often used in conversation to call out someone's transparent jealousy. Mildly mocking; you can say it about yourself self-deprecatingly: 我这是吃不到葡萄说葡萄酸啊。