when push comes to shove

Meaning: いざとなったら、ここぞという時

For Example:

‣ She is not perfect and often makes mistakes, but when push comes to shove, she can do very well.

彼女は完璧やないしミスもよぉするけど、いざという時はよぉやるんよ。

‣ He never wants to rely on anyone, but when push comes to shove, he will ask for help.

彼は基本的に誰にも頼らんけど、ほんまに助けが必要になった時は、ちゃんと頼っとる。

Synonym:

critical moment

ultimately