Function PASSWORD does not treat backslashes literally

When altering the password for a user using the mariadb monitor, backslash characters are not treated literally although in quotation marks:

set password = PASSWORD('abc\def');

Result: User must log in using passwod "abcdef".

set password = PASSWORD('abc\\def');

Result: User must log in using password "abc\def" (typing one backslash with the keyboard).

I find this very confusing and nearly locked myself out of my databases (resetting password for root user).