In 1758, Bentinck was present at an engagement in which the British captured the . In the same month, he was appointed to the command of the sloop , and in that vessel took part later in the expedition under Lord Anson to cover the landing of the Duke of Marlborough at St Malo during the Raid on St Malo. He was then for some time stationed with his sloop off Emden, at the time of the capture of Emden, and while there he became involved in an unfortunate misunderstanding, in the course of which he took the extreme step of placing a Captain Angell, his superior officer, under arrest. The affair, however, was cleared up, the accusations against Captain Angell which had prompted his arrest were fully withdrawn, and on 17 October 1758, Bentinck was promoted to be captain of the frigate . In January 1759, being then still on board the "Fly", he had to aid in the transport of troops to England, and in March of that year, took up his new command. He did not remain long on the "Dover", but was soon removed into the frigate . In this vessel he was employed in 1760 as a cruiser, and distinguished himself highly in an engagement with a French ship of war of very superior weight and armament—the 74-gun "Diadème". About a week after this action, in returning from Plymouth, where he had gone to repair damages, he fell in with and captured the "Jason", a French privateer carrying 8 guns and 52 men. In the following November, he captured off Morlaix the French corvette "Epreuve", carrying 14 guns and 136 men. He remained in the "Niger" until the end of the war in 1762.