Four US Open umpires served up a class-action suit against the US Tennis Association yesterday over claims they were cheated out of wages and overtime.

Steven Meyer, Marc Bell, Larry Mulligan-Gibbs and Aimee Johnson fault the USTA for classifying them as “independent contractors,” saying they were shortchanged for time spent traveling and picking up their credentials.

Their Manhattan federal-court filing — which seeks unspecified monetary damages — also says the association paid a flat rate of between $115 and $200 a day last year, even though umps often work more than eight hours due to lengthy matches and weather delays.