On 20 November, the Soviet armored and motorized forces advanced towards Kalach, with the intention of encircling the 6th Army embroiled in ferocious fighting at Stalingrad. The 22nd Panzer Division, overwhelmed at Petshany by the large number of Soviet tanks, withdrew north to Bol. Donschynka. The Romanian 1st Armored Division, without any available radio contact, tried to advance to Petshany in order to make the junction with the 22nd Panzer Division, but was forced to stop a few kilometers west of Korotovsky by stiff Soviet resistance and numerous counterattacks by Soviet tanks, flowing between the German 22nd and the Romanian 1st, occupying the Varlamovsky and Peralasovsky villages and making the junction with forces coming from Gromsky, thus encircling the 5th Corps. In the 4th Corps' sector, 40 Soviet tanks attacked the 15th Infantry Division but were repulsed by evening with heavy losses. Meanwhile, the 7th Cavalry Division unsuccessfully tried to block the enemy's advance; the right wing of the division, which had fully received the blow, retreated south while the left wing was reassigned to the 9th Infantry Division. Also, the 1st Cavalry Division had to retreat towards Stalingrad and was subordinated to the 6th Army.