The term "up to scratch" is used to say whether someone or something is adequate by general
standards.
The term originates from the boxing world. In the boxing ring is a line called a scratch line. If one of the competitors cannot reach the line, they are deemed to have retired, hence will not be fighting.
The most obvious other phrase to come from boxing is throwing in the towel - something that a boxing manager does to stop the fight. Originally the phrase was throw in the sponge, as sponges were what were used at the ringside.
The phrase "toe the line" is also used in boxing circles - a boxer who cannot walk in a straight line is deemed retired, but this phrase has an earlier, parliamentary root (see node).