E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Scratch (A).
One who in a race starts from the scratch, other runners in the same race being a yard or so in advance. The scratch runner generally is one who has already won a similar race.
1
Coming up to the scratch—up to the mark; about to do what we want him to do. In prize-fighting a line is scratched on the ground, and the toe of the fighter must come up to the scratch.
