Взаимозаменяемые предлоги

at (или in) a pinch - в случае крайней нужды, в крайнем случае; ¬ на худой конец

Marjorie Ferrar was, indeed, of those who can always get money at a pinch... (J. Galsworthy). It was always hard to predict what women would do in a pinch (D. Hewett).