On arrival at Quebec, de Watteville immediately struck up a friendship with the Governor General of Canada, Lieutenant General Sir George Prevost, himself of Swiss origin. He received promotion to Major General on 11 August 1813, although for a time held no appointment. On 17 October, he was appointed to command the district of Montreal, which at the time was threatened by American armies approaching on two fronts. De Watteville immediately called out the militia and began strengthening his defences, but on 26 October, his collected outpost units under Lieutenant Colonel Charles de Salaberry defeated the nearest American army at the Battle of Chateauguay. De Watteville was present and gave full credit to de Salaberry in his dispatch. Unfortunately, Prevost, who was also present, belittled both de Watteville and de Salaberry in his own dispatch, which took precedence over those of his subordinates.