Meaning of "A Masterstroke"

Sin-Ui-Han-Su

A Masterstroke신의 한 수#마인드셋#밈/유행어2010s Meme

This refers to a small adjustment that significantly improves the overall quality of something, or a single, decisive trick or element that tips the scales in a contest.

"We made just one tactical change in the second half, and the whole atmosphere changed completely—it was truly a masterstroke."