 She was responsible for the first Brazilian war action of World War II; she attacked the Brazilian merchant ship "Comandante Lyra" on 18 May 1942, without sinking her, and she was chased by Brazilian aero-naval forces for five days.The submarine managed to escape two attacks by Brazilian B-25 aircraft.On 20 May, the "Barbarigo" met the cruiser and the destroyer ; wrongly recognizing the former as a , Grossi fired two torpedoes at the cruiser.