In 1795, Nauendorf served in Field Marshal Charles Joseph de Croix, Count of Clerfayt's Army of the Lower Rhine, which relieved Mainz. On 10 October, a portion of the Corps of Observation had surprised the French at Hochst; Jourdan was withdrawing his force from the blockade of Mainz. On 13 October, Nauendorf, commander of part of Count Clerfayt's Corps of Observation, sent his cavalry across the Main River, with the infantry following in boats; they surprised and overwhelmed Jourdan's rear guard at Niederhausen, capturing five guns, 30+ wagons and 80 ammunition caissons. On 29 October, Nauendorf captured most of the French siege train and supply wagons evacuated from Mainz. Finally, in that year on 6 November, his victory at Rochenhausen prevented the unification of the French armies of the Rhin-et-Moselle and the Sambre-et-Meuse.