With the Axis invasion of the Soviet Union that month, Ustinov was deployed on the Western Front. He was assigned to the 6th Cavalry Division, then at Białystok, but with the rapid advance of enemy forces, found himself cut off and unable to reach his unit. He returned to Mogilev and was placed with the reserve personnel. He subsequently saw action at the Battle of Smolensk, and at the fighting around Vyazma. During the engagements Ustinov's detachment was one of the many trapped by German encirclement. The detachment was eventually able to break through the encirclement and withdraw to safety, a fact the commander of the assembly point credited to Ustinov's actions. Ustinov later recalled how he greeted the men with "Comrades, I'm from military counterintelligence! Now we will organize and make a breakout. I checked: it will be possible to break through here. If someone is scared and wants to surrender, I will shoot him with the power given to me by the Motherland!" Later in the war he saw action with the 11th Guards Army as part of the NKVD Special Division, taking part in the offensives in Operation Kutuzov in 1943, and Operation Bagration in 1944. From April 1944, he was the head of SMERSH detachment with the 83rd army field , and from January 1945, the head of SMERSH of the 3rd detachment of a separate tank regiment of the 3rd Belorussian Front. He was credited with the exposure of over 20 "Abwehr" agents.