During the forced crossing of the Spree River in the Rummelsburg area (Germany), the enemy prevented our combat units from crossing to the western bank with heavy artillery, mortar, and Panzerfaust fire. Nevertheless, Lieutenant Kovalchuk and his platoon were the first to cross; they repelled two enemy counterattacks, inflicting heavy losses on the opposing force. In this engagement, his platoon killed 72 German soldiers and officers and took 13 prisoners.

During the street fighting on Schliesser-Strasse, when the company commander was put out of action, Kovalchuk assumed command; he boldly and decisively led the assault on 49 buildings. In these street battles, he demonstrated exemplary heroism and skill in commanding his unit while minimizing casualties. During the engagement, he destroyed 52 enemy firing points and captured 192 German soldiers and officers. Although wounded, he refused to leave the battlefield, continuing to return fire and command his company.