At the time of outbreak of the April War in 1941, Spasić was a lieutenant on the destroyer stationed in Dobrota (Bay of Kotor). He was the officer in charge of the ship's torpedoes and mines. "Zagreb" and the destroyers and were the most recent Royal Yugoslav Navy ships at that time. On the 6th of April, they were the target of an air attack by five "Regia Aeronautica" bombers. The bay was under attack by Italian aircraft once again on April 13, but the bombing did not damage "Zagreb". Later, on the 15th of April, the Yugoslav Royal Army asked for a truce. The crews of the ships stationed in the Bay of Kotor were instructed not to open fire on the Axis forces and to surrender peacefully. They were also ordered to not destroy anything.