Student or Learner
"There is a sense here that if it truly is to be the greatest World Cup ever the host, Brazil, need to be in the final on Sunday here, in Rio, against Argentina or the Netherlands on Sunday. To lose tonight would be unthinkable. Germany present formidable opposition. Tonight, something simply has to give."
The above is from a journalist reporting ahead of semi-final World Cup.
What does the underlined part mean? Is it a fixed idiom?
Yes. 'Something's got to give' (with minor variations as above) means that one of them must lose.