luck of the draw

the luck of the draw (the results of chance; the lack of any choice) — лотерея; слепое везение; зигзаг удачи; случай, случайная удача/неудача, игра случая
If something is the luck of the draw, it is the result of chance and you have no control over it that's/it's just the luck of the draw — это (уж) как повезёт; здесь все зависит от случая, от везения

Example 1: You can't choose who you play against. It's just the luck of the draw. (CALD)
Example 2: The team was assembled by chance. It was just the luck of the draw that we could work so well together. (McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)

Related Vocabulary:
A draw is a competition in which you win if the number on your ticket is chosen.