a close-run thing

idiomPart ofclose

a close-run thing — idiom

1. A competition or election that is won or lost by a very small margin.

1.idiom
Definition

A competition or election that is won or lost by a very small margin.

Example

The election was a close-run thing, decided by only 100 votes.

The match was a close-run thing, with the winner scoring in the last minute.