In time-pressure action esports games, a player’s mechanical skill refers to the ability to quickly and accurately control input devices such as a keyboard or mouse. In this study, we present a novel methodology to quantify and operationalize mechanical skills commonly required in game titles played with the same set of input devices (i.e., general mechanical skill). From this, differences in mechanical skills between players can be compared on a standard basis, regardless of game title, which offers new possibilities for esports talent development. As a result of partial least squares path modeling based on data from 292 players of four different game titles played with keyboard and mouse, we show that general mechanical skill is a valid construct and that it accounts for approximately 21% of the variance in players’ in-game achievement (or rank). To maximize impact, our software is released to the public, enabling anyone to operationalize general mechanical skills in time-pressure action esports games played with keyboard and mouse.