Rybalko was an able Commander of Tank Armies who is credited with liberating Prague. A military instructor from 1941-42, he was appointed Commander of the 5th Guards Tank Army in the summer of 1942 and then of the 3rd Guards Tank Army. He was involved in the Stalingrad counteroffensive where he crossed the Don in December 1942 to defeat a German-Hungarian Army in the Voronezh region. After the Battle of Kursk, Rybalko managed to cross the Dnieper and establish a bridgehead on the western bank. He was also involved in the liberation of the Ukraine and in the capture of Lvov in July 1944.