Vertelko joined the Red Army in October 1943, initially undergoing training with the 72nd Reserve Training Rifle Regiment of the 9th Rifle Division. He would later recall that he first took the oath on 3 November 1943. With the completion of his training, he was dispatched to the front in March 1944, serving as a scout in the 75th Motorcycle Reconnaissance Battalion of the 29th Tank Corps, with the 5th Guards Tank Army. He had a narrow escape when a comrade offered to exchange trenches with him prior to a German counterattack. A shell hit Vertelko's former trench, killing the man he had exchanged with. Vertelko went on to see action in many of the battles as the Red Army pushed back the occupying forces. He was awarded the Medal "For Courage" after the liberation of Minsk, and went on to participate in the battles of the Vilnius offensive, resulting in the liberation of Molodechno, Borisov, Kaunas, and Vilnius.