Our teammates were such a letdown that we lost the match.
Tips
history
给力 (gěilì, awesome / impressive) became a viral internet word around 2010 after appearing in a Chinese-dubbed 西游记 (Xīyóujì, Journey to the West) parody. It even broke into the People's Daily headline that year. 不给力 is its negative twin — used constantly online to mean 'weak / underwhelming.'
register
Both 给力 and 不给力 are casual/internet register. Fine in messaging, social media, and friendly conversation; avoid in formal writing where 不理想 (bù lǐxiǎng, unsatisfactory) or 表现不佳 (biǎoxiàn bù jiā, poor performance) fit better.
