A process for upgrading a diesel fuel, includes the steps of providing a diesel fuel feedstock; hydrogenating the feedstock at a pressure of less than about 600 psig so as to provide a hydrogenated product wherein a portion of the feedstock is converted to alkyl-naphthene-aromatic compounds; and selectively oxidizing the hydrogenated product in the presence of a catalyst so as to convert the alkyl-naphthene-aromatic compounds to alkyl ketones. A catalyst and oxygen-containing Diesel fuel are also provided.